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Full text of "Principles of zoology : touching the structure, development, distribution and natural arrangement of the races of animals, living and extinct; with numerous illustrations. For the use of schools and colleges. Pt. I. Comparative physiology."

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Come and take choice ofaCCmy Cibrary, 
And so beguiCe thy sorrow. " Shakespeare 



Touching the Structure, Development, Distribution and Natural 
Arrangement of the Races of Animals, living and extinct ; with numer- 
ous Illustrations. For the use of Schools and Colleges. Part 1. Com- 
parative Physiology. 



" The design of this work is to furnish an epitome of the leading princi- 
ples of the science of Zoology, as deduced from the present state of 
knowledge, so illustrated as to be intelligible to the beginning student. No 
similar treatise now exists in this country, and, indeed, some of the topics 
have not been touched upon in the language, unless hi a strictly technical 
form, and in scattered articles." 

" Being designed for American students, the illustrations have been drawn, 
as far as possible, from American objects. . . . Popular names have 
been employed as far as possible, and to the scientific names, an English 
termination has generally been given. The first part is devoted to Com- 
parative Physiology, as the basis of Classification ; the second, to System- 
atic Zoology, in which the principles of Classification will be applied, and 
the principal groups of animals briefly characterized." 


" This work has been expected with great interest. It is not simply a 
system by which we are taught the classification of Animals, but it is 
really what it professes to be, the ' Principles of Zoology,' carrying us on 
step by step, from the simplest truths to the comprehension of that infinite 
plan which the Author of Nature has established. . . . This book places 
us in possession of information half a century in advance of all our element- 
ary works on this subject. . . . No work of the same dimensions has 
ever appeared in the English language, containing so much new and valu- 
able information on the subject of which it treats." Prof. James Hall, in 
the, Albany Journal. 

" A work emanating from so high a source as the ' Principles of Zoology,' 
hardly requires commendation to give it currency. The public have become 
acquainted with the eminent abilities of Prof. Agassiz through his lectures, 
and are aware of his vast learning, wide reach of mind, and popular mode 
of illustrating scientific subjects. In the preparation of this work, he has 
had an able coadjutor in Dr. A. A. Gould, a frequent contributor to the 
Transactions of the Boston Society of Natural History, and at present 
engaged upon the department of Conchology, for the publication of the late 
exploring expedition. The volume is prepared for the student in zoological 
science ; it is simple and elementary in its style, full in its illustrations, 
comprehensive in its range, yet well condensed, and brought into the narrow 
compass requisite for the purpose intended." Sillimaii's Journal, June, 1848. 

" The work is admirably adapted to the use of schools and colleges, and 
ought to be made a study in all our higher seminaries, both male and 
female." New York Observer. 

" To the testimony which is furnished by their distinguished scholarship, 
we may add, however, that the classifications of the work are so admirably 
arranged, and its descriptions given with so much simplicity and clearness 
of language, that the book cannot fail of its practical aim to facilitate 
the progress of the beginning student. It is a work for schools." 

New York Recorder. 


" The announcement of this work some time ago, as being in a course of 
preparation, excited a high degree of interest among teachers, students, 
and the friends of science. The names of its authors gave ample assurance 
that it was no compilation drawn from other works, no mere reconstruction 
of existing materials. The work will undoubtedly meet the expectations 
that have been formed of it, and already it has been adopted as a text-book 
in several colleges. It breaks new ground ; as is said in the preface, 'some 
of its topics have not been touched upon in the language, unless in a strictly 
technical form, and in scattered articles.' The volume exhibits throughout 
great labor and care in preparing it for the public eye, and for the use of 
students. As it has no rival, we suppose its adoption will be almost univer- 
sal in literary institutions, and it will do much to awaken in the minds of 
multitudes an enthusiastic love of natural history." Christian Reflector $ 

" This work is designed as a text book for schools and colleges, and as 
an exposition of the interesting science of which it treats, it has many ob- 
vious advantages over any other treatise extant. It is the joint production 
of two gentlemen, whose researches in natural history have enlarged the 
domain'of human knowledge, and one of whom stands confessedly at the 
head of the science of the age. It hence contains the latest and most 
approved classifications, with explanations and illustrations borrowed from 
the forms of animated nature, both living and extinct, and made accurate 
and perfect by the fullest acquaintance with the present condition of zoo- 
logical science. As a text book it is admirably conceived. 

" The presence of Prof Agassiz in the United States, has given a new 
impulse to every branch of natural history, and we are happy to find him 
thus associated with Dr. Gould, one of our leading American naturalists, 
in explaining his favorite science to the youth of our schools and colleges." 
Providence Journal. 

"No such work had previously appeared in our country. The produc- 
tion is worthy of the great names under whose care it has been prepared. 
Prof. Agassiz has a world-wide reputation, and Dr. Gould is regarded by the 
scientific men of Europe as the most eminent naturalist of our country. 
Schools and Academies will find it opens up a new and attractive study 
for the young, and in no country is there a finer field opened up to the 
naturalist than in our own." Cliristian Alliance, Boston. 

" Anew and highly valuable publication, intended for a school book, but 
which will be found equally interesting and important for all to study. . . . 
Such a work as this has long been a great desideratum, and we rejoice that 
a want so strongly felt, has now, at length, been so well and so completely 
supplied." Boston Atlas. 

" This is entirely a new field in American elementary literature, no simi- 
lar treatise existing in this country. At fii'st sight, the work appeared to 
us too abstruse for beginners, and" for the iise of those whom the author 
aims to benefit the scholars in our common schools. A more careful 
examination convinces us that any teacher or scholar, who is in earnest to 
understand the subject, will find the application necessary at the commence- 
ment comparatively trifling, while the subsequent benefit will be immense. 
This is the first volume of the woi'k, and is devoted to Comparative Physi- 
ology, on which branch it is exceedingly complete. It is freely illustrated 
with the necessary wood cuts. The names of the authors will be a higher 
guarantee for scientific accuracy than any judgment we might pronounce." 
New York Commercial Advertiser. 

" It is designed chiefly for the use of schools and colleges, and as an 
epitome of the subject on which it treats, contains more in a small space, 
than any book of the kind that has yet fallen under our notice." Saturday 
Gleaner, Philadelphia. 

IV. Modern Age. 
TTT. Tertiary Age. 

II. Secondary Age. 

I. Paleozoic Age. 
Metamorphic Rocks. 

Upper Tertiary Formation. 

Lower Tertiary 

Upper Silurian 
Lower Silurian 


















Entered according to Act of Congress, in the year 1848, 

in the Clerk's Office of the District Court of the District of Massachusetts. 




THE design of this work is to furnish an epitome of the 
leading principles of the science of Zoology, as deduced 
from the present state of knowledge, so illustrated as 
to be intelligible to the beginning student. No similar 
treatise now exists in this country, and indeed some of 
the topics have not been touched upon in the lan- 
guage, unless in a strictly technical form, and in scat- 
tered articles. On this account, some of the chapters, 
like those on Embryology, and Metamorphosis, may 
at first seem too abstruse for scholars in our common 
schools. This may be the case, until teachers shall have 
made themselves somewhat familiar with subjects com- 
paratively new to them. But so essential have these 
subjects now become to a correct interpretation of phi- 
losophical zoology, that the study of them will hereafter 
be indispensable. They furnish a key to many phe- 
nomena which have been heretofore locked in mystery. 

Being designed for American students, the illustra- 
tions have been drawn, as far as possible, from American 
objects ; some of them are intended merely as ideal 
outlines, which convey a more definite idea than if accu- 


rately drawn from nature ; others have been left imper- 
fect, except as to the parts especially in question ; a large 
proportion of them however, are accurate and original. 
Popular names have been employed as far as possible, 
and to the scientific names an English termination has 
generally been given. Definitions of those least likely 
to be understood, may be found in the Index. 

The principles of Zoology developed by Professor 
Agassiz in his published works have been generally 
adopted in this, and the results of many new researches 
have been added. 

The authors gratefully acknowledge the aid they have 
received in preparing the illustrations and working out 
the details from Mr. E. Desor, for many years an asso- 
ciate of Professor Agassiz, from Count Pourtales and 
E. C. Cabot, Esq., and also from Prof. Asa Gray, by 
valuable suggestions in the revision of the letter-press. 

The first part is devoted to Comparative Physiology 
as the basis of Classification ; the second to Systematic 
Zoology, in which the principles of Classification will 
be applied, and the principal groups of animals will be 
briefly characterized. 

Should our aim be attained, this work will produce 
more enlarged ideas of man's relations to Nature, and 
more exalted conceptions of the plan of Creation and 
its Great Author. 

BOSTON, JUNE 1, 1848. 







Organized and Unorganized Bodies 11 

Elementary Structure of Organized Bodies 13 

Differences between Animals and Plants 17 




Of the Nervous System and General Sensation 20 





Of tJie Special Senses 24 

1. Of Sight 24 

2. Of Hearing 31 

3. Of Smell ... . 36 

4. Of Taste .... .... 38 

5. Of Touch 39 

6. Of the Voice . 40 






Apparatus of Motion 49 


Of Locomotion 55 

1. Plan of the Organs of Locomotion ... 58 

2. Of Standing, and the Modes of Progression . . 64 

Walking . 66 

Running 67 

Leaping 67 

Climbing 68 

Flying 68 

Swimming .69 




Of Digestion 

Digestive Tube 73 

Chymification 75 

Chylification 76 

Mastication 77 

Insalivation ... ... 











Of the Egg 102 

Form of the Egg 103 

Formation of the Egg 104 

Ovulation 105 

Laying 105 

Composition of the Egg 107 

Development oftJie Young within the Egg 109 

Zoological Importance of Embryology 122 



Gemmiparous and Fissiparoiis Generation ..... 125 

Alternate and Equivocal Reproduction 127 


Consequences of Alternate Generation 136 






General Laws of Distribiition .... . 154 


Distribution of the Faunas 161 

I. Arctic Fauna 164 

n. Temperate Faunas 166 

III. Tropical Faunas 172 

Conclusions 175 



Structure of tlie Earth's Crust ....'.. 182 


Ages of Nature 189 

Paleozoic Age 191 

Secondary Age 195 

Tertiary Age 201 

Modern Age ... 203 

Conclusions 205 


FRONTISPIECE. The diagram opposite the title page is intended to present, 
at one view, the distribution of the principal types of animals, and the order 
of their successive appearance in the layers of the earth's crust. The four 
Ages of Nature, mentioned at page 190, are represented by four zones, of 
different shades, each of which is subdivided by circles, indicating the num- 
ber of formations of which they are composed. The whole disc is divided 
by radiating lines into four segments, to include the four great departments 
of the Animal Kingdom ; the Vertebrates, with Man at their head, are placed 
in the upper compartment, the Articulates at the left, the Mollusks at the right, 
and the Radiates below, as being the lowest in rank. Each of these com- 
partments is again subdivided to include the different classes belonging to it, 
which are named at the outer circle. At the centre is placed a figure to re- 
present the primitive egg, with its germinative vesicle and germinative dot 
(278), indicative of the universal origin of all animals, and the epoch of life 
when all are apparently alike (275, 276). Surrounding this, at the point 
from which each department radiates, are placed the symbols of the several 
departments, as explained on page 124. The zones are traversed by rays 
which represent the principal types of animals, and their origin and termination 
indicates the age at which they first appeared or disappeared, all those 
which reach the circumference being still in existence. The width of the 
ray indicates the greater or less prevalence of the type at different geo- 
logical ages. Thus, in the class of Crustaceans, the Trilobites appear to 
commence in the earliest strata, and to disappear with the carboniferous 
formation. The Ammonites also appeared in the Silurian formation, and did 
not become extinct before the deposition of the Cretaceous rocks. The 
Belemnites appear in the lower Oolitic beds ; many forms commence in the 
Tertiary ; a great number of types make their appearance only in the Modern 


age ; while only a few have continued from the Silurian, through every 
period to the present. Thus, the Crinoids were very numerous in the 
Primary Age, and are but slightly developed in the Tertiary and Modern 
Age. It is seen, at a glance, that the Animal Kingdom is much more diver- 
sified in the later, than in the earlier Ages. 

Below the circle is a section, intended to show more distinctly the re- 
lative position of the ten principal formations of stratified rocks (461), com- 
posing the four great geological ages ; the numerals corresponding to those on 
the ray leading to Man, in the circular figure. See also figure 154. 

The CHART OF ZOOLOGICAL REGIONS, page 163, is intended to show the 
limits of the several Faunas of the American Continent, corresponding to the 
climatal regions. And as the higher regions of the mountains correspond in 
temperature to the climate of higher latitudes, it will be seen that the northern 
temperate fauna extends, along the mountains of Mexico and Central Amer- 
ica, much farther towards the Equator, than it does on the lower levels. In 
the same manner, the southern warm fauna extends northward, along the 


1. Simple cell, magnified, as seen in the house-leek. 

2. Cells when altered by pressure upon each other ; from the pith of elder. 

3. Nucleated cells (#), magnified ; b, nucleolated cells. 

4. Cartilaginous tissue from a horse, magnified 120 diameters. 

5. Osseous tissue from a horse, magnified 450 diameters. 

6. Nervous fibres, showing the loops as they terminate in the skin of a frog. 

7. Gray substance of the brain, magnified. 

8. Head of an embryo fish, to show its cellular structure throughout. 

9. Diagram, to show the nervous system of the Vertebrates, as found in 

a monkey. 

10. Diagram of the nervous system of the Articulates, as seen in a lobster. 

11. Diagram of the nervous system of the Mollusks, as found in Natica lieros. 

12. Diagram of the nervous system of the Radiates, as found in Scutella 

(Echinarachnius par ma) . 

13. Section of the eye. a, optic nerve ; b, sclerotic coat ; c, choroid coat ; 

d, retina ; e, crystalline lens ; /, cornea ; g, iris ; k, vitreous body ; 
ij chamber, divided by the iris. 

14. Diagram, showing the effect of the eye on rays of light. 

15. Position of the eye of the snail. 

16. Eyes (ocelli) of a spider. 

17. Eye-spots of a star-fish (Echinaster sanguinolentus) . 

18. Compound eyes, showing the arrangement of the facettes, and their con- 

nection with the optic nerve, as seen in a crab's eye. 

19. Diagram of the human ear, to show the different chambers, canals, and 




20. Tympanum and small bones of the ear, twice the natural size ; c, tym- 

panum ; m, malleus ; n, incus ; o, orbiculare ; s, stapes. 

21. Section of the brain of a crow, showing- the origin of the nerves of the 

special senses. 

22. Diagram of the larynx, in man. 

23. Larynx of the merganser (Mergus merganser} . 

24. Nests of Ploceus Philippinus, male and female. 

25. Distribution of nerves to the muscular fibres. 

26. Test, or crust-like covering of an Echinoderm ( Cidaris) . 

27. Muscular ribbons of the willow-moth ( Cossus ligniperda). 

28. Vertebra of a cod-fish. 

29. Disposition of the muscles of the trout (Salmo tnitta}. 

30. Disposition of the muscles of an owl (Strix brachyotis). 

31. Jelly-fishes (Stomobrachium crudatum, Hippocrene BougainviUii). 

32. Leech, showing the terminal cups. 

33. Portion of a Nereis, showing the gills as organs of motion. 
34 - 43. Modifications of the fore-arm. 

34. Monkey. 35. Deer. 36. Tiger. 37. Whale. 38. Bat. 
39. Pigeon. 40. Turtle. 41. Sloth. 42. Mole. 43. Whale. 

44. Leg of a beetle. 

45. Leg of a lizard. 

46. Skeleton of a tiger. 

47. Cuttle-fish (Loligo ittecebrosa}. 

48. Sea-anemone (Actinia marginata) ', a, mouth ; , stomach ; c, general 

cavity of the body. 

49. Planaria, showing the mouth, stomach, and its branches. 

50. Jaws, stomach, and intestine of a sea-urchin (Echinus lividus). 

51. Plan of the digestive organs of an Insect. 

52. Plan of the digestive organs of a land-slug ( TebennopJionis Caroliniensis) . 

53. Globules of chyle. 

54. Portion of intestine, showing the lacteals of man, and their entrance 

into a vein. 

55. Jaws of an Echinoderm (Echinarachnius parma). 

56. Jaws of a sea-urchin (Echinus granulatus). 

57. Beak of a cuttle-fish. 

58. Portion of the tongue of a Mollusk (Natica keros), magnified. 

59. Jaws of an Annelide (Nereis). 

60. Trophi (organs for taking food) of a beetle. 

61. " of a bee. 

62. 63. " of a squash-bug. 

64. " of a butterfly. 

65. " of a Rotifer (Brachionus). 

66. Jaws of ditto, magnified. 



67. Skull of a tiger, showing the muscles for mastication. 

68. Head of a snapping-turtle (Emysaimts serpentina) . 

69. Head of a "Whale, showing the whalebone. 

70. Head of an ant-eater. 

71. Head of an alligator. 

72. Head of a skate-fish (Myliobatis'), showing the palate bone. 

73. Head of a monkey, showing the three different kinds of teeth. 

74. Teeth of an insectivorous animal, the mole. 

75. Teeth of a carnivorous animal, the tiger. 

76. Teeth of a rodent. 

77. A polyp ( Tubularia indivisa) ; m> mouth ; 0, ovaries ; p^ tentacles. 

78. Blood globules in man, magnified. 

79. " in birds, 

80. " " in reptiles, " 

81. " " in fishes, " 

82. Portion of a vein opened, to show the valves. 

83. Network of capillary vessels. 

84. Dorsal vessel of an insect, with its valves. 

85. Cavities of the heart of mammals and birds. 

86. " " of a reptile. 

87. " of a fish. 

88. Heart and blood vessels of a gasteropod mollusk (Natica). 

89. Tracheae, or air tubes of an insect ; s, stigmata ; t } trachea. 

90. Relative position of the heart and lungs in man. 

91. Respiratory organs of a naked mollusk (Polycera iUuminata). 

92. Respiratory organs (gills) of a fish. 

93. Vesicles and canals of the salivary glands. 

94. Section of the skin, magnified, to show the sweat glands ; a, the leather ; 

b, blood-layer ; f, epidermis ; g, gland imbedded in the fat-layer (f), 

95. Egg of a skate-fish (Myliobatis') . 

96. Egg of hydra. 

97. Egg of snow-flea (Podurella). 

98. Section of an ovarian egg ; d, germinative dot ; g-, germinative vesicle ; 

s, shell-membrane ; v : vitelline membrane. 

99. Egg cases of Pyrula. t 

100. Monoculus bearing its eggs, a a. < 

101. Section of a bird's egg ; #, albumen ; c, chalaza ; e, embryo; s, shell ; 

y, yolk. 

102. Cell-layer of the germ. 

103. Separation of the cell-layer into three layers ; s, serous or nervous layer ; 

m, mucous or vegetative layer ; v, vascular or blood-layer. 

104. Embryo of a crab, showing its incipient rings. 

105. Embryo of a vertebrate, showing the dorsal furrow. 



106-8. Sections of the embryo, showing the formation of the dorsal canal. 

109. Section, showing- the position of the embryo of a vertebrate, in relation 

to the yolk. 

110. Section, showing the same in an articulate (Podurella}. 

11^-22. Sections, showing the successive stages of development of the em- 
bryo of the white-fish, magnified. 

123. Young white-fish just escaped from the egg, with the yolk not yet fully 

taken in. 

124, 125. Sections of the embryo of a bird, showing the formation of the 

allantois ; e, embryo ; x x, membrane rising to form the amnios ; 
, allantois ; ?/, yolk. 

126. The same more fully developed. The allantois (a} is further developed, 

and bent upwards. The upper part of the yolk (dd) is nearly 
separated from the yolk sphere, and is to become the intestine. The 
heart (k) is already distinct, and connected by threads with the 
blood-layer of the body. 

127. Section of the egg of a mammal ; t>, the thick vitelline membrane, or 

chorion ; y, yolk ; s, germinative dot ; g, germinative vesicle. 

128. The same, showing the empty space () between the vitelline sphere 

and chorion. 

129. Shows the first indications of the germ already divided in two layers, 

the serous layer (s} : and the mucous layer (m). 

130. The mucous layer (m) expands over nearly half of the yolk, and be- 

comes covered with many little fringes. 

131. The embryo (e) is seen surrounded by the amnios (), and covered by 

a large allantois (a) ; p e, fringes of the chorion ; pm, fringes of the 

132. Hydra, showing its reproduction by buds. 

133. Vorticella, showing its reproduction by division. 

134. Polyps, showing the same. 

135. A chain of Salpae. 

136. An individual salpa ; m, the mouth ; a, embryos. 

137. Cercaria, or early form of the Distoma. 

138. Distoma, with its two suckers. 

139. Nurse of the Cercaria. 

140. The same, magnified, showing the included young. 

141. Grand nurses of the Cercaria, enclosing the young nurses. 

142. Stages of development of a jelly-fish (Medusa); a, the embryo in Us 

first stage, much magnified ; , summit, showing the mouth ; c, /, 
g, tentacles shooting forth ; e, embryo adhering, and forming a pedi- 
cle ; h, t, separation into segments ; d, a segment become free ; 
, form of the adult. 

143. Portion of a plant-like polyp ( Campanula-rick) ; a, the cup which bears 

tentacles ; b, the female cup, containing eggs ; c, the cups in which 
the young are nursed, and from which they issue 



144. Young of the same, with its ciliated margin, magnified. 

145. Eye of the perch, containing parasitic worms (Distoma). 

146. One of the worms magnified. 

147. Transformations of the canker-worm ( Geometra vernalis] ; , the can- 

ker-worm ; ^ its chrysalis ; c, female moth ; d, male moth. 

148. Metamorphoses of the duck-barnacle (Anatifa) ; a, eggs, magnified ; , 

the animal as it escapes from the egg ; c, the stem and eye appear- 
ing, and the shell enclosing them; d : animal removed from the 
shell, and further magnified ; e, /, the mature barnacle, affixed. 

149. Metamorphoses of a star-fish (Echinaster sangidnolentus), showing the 

changes of the yolk (e) ; the formation of the pedicle (p) ; and the 
gradual change into the pentagonal and rayed form. 

150. Comatula, a West India species, in its early stage, attached to a stem. 

151. The same detached, and swimming free. 

152. Longitudinal section of the sturgeon, to show its cartilaginous vertebral 


153. Amphioxus, natural size, showing its imperfect organization. 

154. Section of the earth's crust, to show the relative positions of the rocks 

composing it ; E, plutonic or massive rocks ; M, metamorphic 
rocks ; T, trap rocks ; _L, lava. 1. Lower Silurian formation ; 2. 
Upper Silurian ; 3. Devonian ; 4. Carboniferous ; 5. Trias, or 
Saliferous ; 6. Oolitic ; 7. Cretaceous ; 8. Lower Tertiary or Eo- 
cene ; 9. Upper Tertiary, or Miocene, and Pleiocene ; 10. Drift. 

155. Fossils of the Paleozoic age ; a, Lingula prima ; b, Leptsena alternata ; 

c, Euomphalus hemisphericus ; d, Trocholites ammonius ; e, Avicula 
decussata ; f. Bucania expansa ; g, Orthoceras fusiforme ; /', Cya- 
thocrinus ornatissimus, Hall ; j, Cariocrinus ornatus, Say ; , Melo- 
crinus amphora, Goldf. ; /, Columnaria alveolata ; m, Cyatho- 
phyllum quadrigeminum, Goldf. ; n, o, Caninia flexuosa ; p, Chse- 
tetes lycoperdon. 

156. Articulata of the Paleozoic age ; o, Harpes ; b, Arges ; c, Brontes ; d, 

Platynotus ; e, Eurypterus remipes. 

157. Fishes of the Paleozoic age ; a, Pterichthys ; b, Coccosteus ; c , Dipte- 

rus ; d, palatal bone of a shark ; e^ spine of a shark. 

158. Representations of the tracks of supposed birds and reptiles in the sand- 

stone rocks. 

159. Supposed outlines of Ichthyosaurus (a), and Plesiosaurus (b). 

160. Supposed outline of Pterodactyle. 

161. Shells of the Secondary age : a, Terebratula ; b, Goniomya ; c, Trigo- 

nia ; c?, Ammonite. 

162. Supposed outline of the cuttle-fish (), from which the Belemnite was 


163. Radiata from the Secondary age : a, Lobophyllia flabellum ; b, Litho- 



dendron pseudostylina ; c, Pentacrinus briareus ; cl, Pterocoma 

pinnata ; e, Cidaris ; /, Dysaster ; g, Nucleolites. 

164. Shells of the Cretaceous formation ; , Ammonites ; l t Crioceras ; c, 

Scaphites ; d, Ancyloceras ; e, Hamites ; f\ Baculites ; g, Turrilites. 

165. Shells of the Cretaceous formation : a, Magas ; b, Inoceramus ; c, Hip- 

purites ; d, Spondylus ; e, Pleurotomaria. 

166. Radiata from the Cretaceous formation : a, Diploctenium cordatum ; 

b, Marsupites ; d, Galerites ; c, Salenia ; e, Micraster cor-angninum. 

167. Nummulite. 

168. Supposed outline of Paleotherium. 

169. Supposed outline of Anoplotherium. 

170. Skeleton of the Mastodon, in the Cabinet of Dr. J. C. "Warren. 


EVERY art and science has a language of technical terms 
peculiar to itself. With those terms every student must 
make himself familiarly acquainted at the outset ; and first 
of all, he will desire to know the names of the objects about 
which he is to be engaged, 

The names of objects in Natural History are double, that 
is to say, they are composed of two terms. Thus, we speak 
of the white-bear, the black-bear, the hen-hawk, the sparrow- 
hawk ; or, in strictly scientific terms, we have Felis leo, the 
lion, Felis tigris, the tiger, Felis catus, the cat, Canis lupus, 
the wolf, Canis vulpes, the fox, Canis familiaris, the dog, 
&c. They are always in the Latin form, and consequently 
the adjective name is placed last. The first is called the 
generic name ; the second is called the trivial, or spe- 
cific name. 

These two terms are inseparably associated with every ob- 
ject of which we treat. It is very important, therefore, to have 
a clear idea of what is meant by the terms genus and species ; 


and although the most common of all others, they are not 
the easiest to be clearly understood. The Genus is founded 
upon some of the minor peculiarities of anatomical struc- 
ture, such as the number, disposition, or proportions of the 
teeth, claws, fins, &c., and usually includes several kinds. 
Thus, the lion, tiger, leopard, cat, &c., agree in the struc- 
ture of their feet, claws, and teeth, and they belong to the 
genus Felis ; while the dog, fox, jackal, wolf, &c., have 
another and a different peculiarity of the feet, claws, and 
teeth, and are arranged in the genus Canis. 

The Species is founded upon less important distinctions, 
such as color, size, proportions, sculpture, &c. Thus we 
have different kinds, or species, of duck, different species of 
squirrel, different species of monkey, &c., varying from 
each other in some trivial circumstance, while those of 
each group agree in all their general structure. The spe- 
cific name is the lowest term to which we descend, if 
we except certain peculiarities, generally induced by some 
modification of native habits, such as are seen in domestic 
animals. These are called varieties, and seldom endure 
beyond the causes which occasion them. 

Several genera which have certain traits in common are 
combined to form a family. Thus, the alewives, herrings, 
shad, &c., form a family called Clupeidse ; the crows, 
blackbirds, jays, &c., form the family Corvidae. Families 
are combined to form orders, and orders form classes, and 
finally, classes are combined to form the four primary divi- 
sions of the Animal Kingdom, namely, the departments. 

For each of these groups, whether larger or smaller, we 
involuntarily picture in our minds an image, made up of the 
traits which characterize the group. This ideal image is 
called a TYPE, a term which there will be frequent occasion 
to employ, in our general remarks on the Animal Kingdom. 
This image may correspond to some one member of the 


group ; but it is rare that any one species embodies all our 
ideas of the class, family, or genus to which it belongs. 
Thus, we have a general idea of a bird ; but this idea does 
not correspond to any particular bird, or any particular 
character of a bird. It is not precisely an ostrich, an owl, 
a hen, or a sparrow ; it is not because it has wings, or 
feathers, or two legs ; or because it has the power of flight, 
or builds nests. Any, or all of these characters would not 
fully represent our idea of a bird ; and yet every one has a 
distinct ideal notion of a bird, a fish, a quadruped, &c. It 
is common however, to speak of the animal which embodies 
most fully the characters of a group, as the type of that 
group. Thus, we might perhaps regard an eagle as the 
type of a bird, the duck as the type of a swimming-bird, and 
the mallard as the type of a duck. 

As we must necessarily make frequent allusions to ani- 
mals, with reference to their systematic arrangement, it 
seems requisite to give a sketch of their classification in as 
popular terms as may be, before entering fully upon that 
subject, and with particular reference to the diagram front- 
ing the title-page. 

The Animal Kingdom consists of four great divisions 
which we call DEPARTMENTS, namely, 

I. The department of Vertebrates. 

II. The department of Articulates. 

III. The department of Mollusks. 

IV. The department of Radiates. 

I. The department of VERTEBRATES includes all animals 
which have an internal skeleton, with a back-bone for its 
axis. It is divided into four classes. 

1. Mammals (animals which nurse their young). 

2. Birds. 

3. Reptiles. 

4. Fishes. 


The class of MAMMALS is subdivided into three orders. 
a. Beasts of prey (Carnivora). 
ft. Those which feed on vegetables (Herbivora). 
c. Animals of the whale kind (Cetaceans]. 

The class of BIRDS is divided into four orders, namely, 

a. Birds of prey (Incessores}. 

b. Climbers (Scansores). 

c. Waders (Grallatores). 

d. S\vimmers (Natatores). 

The class of REPTILES is divided into five orders. 

a. Large reptiles with hollow teeth, most of which are 

now extinct (Rliizodonts). 

b. Lizards (Lacertans). 

c. Snakes (Ophidians}. 

d. Turtles (Chelonians). 

e. Frogs (Batrachians). 

The class of FISHES is divided into four orders : 

a. Those with enamelled scales, like the gar-pike 

(Ganoids], fig. 157. 

b. Those with the skin like shagreen, as the sharks 

and skates (Placoids). 

c. Those which have the edge of the scales toothed, 

and usually with some bony rays to the fins, as 
the perch (Ctenoids). 

d. Those whose scales are entire, and whose fin rays 

are soft, like the salmon (Cycloids"). 

II. Department of ARTICULATES. Animals whose body is 
composed of rings or joints. It embraces three classes. 

1. Insects. 

2. Crustaceans, like the crab, lobster, &c. 

3. Worms. 


The class of INSECTS includes three orders. 

a. Those which have jaws for dividing their food 
(Manducata) fig. 60. 

1}. Those with a trunk for sucking fluids, like the but- 
terfly, (Suctoria] fig. 62 64. 

c. Those destitute of wings, like spiders, fleas (Apterd). 

The class CRUSTACEANS may be divided as follows : 

a. Those furnished with a shield like the crab and 

lobster (Malacostracd). 

b. Such as are not thus protected (Entomostraca). 

c. An extinct race, intermediate between these two 

(TriloUtes) fig. 156. 

The class of WORMS comprises three orders : 

a. Those which have thread-like gills about the head 

( Tubulibranchiates). 

b. Those whose gills are placed along the sides (Dor- 


c. Those which have no exterior gills, like the earth- 

worm (Abranchiates). 

III. The department of MOLLUSKS is divided into three 
classes, namely : 

1. Those which have arms about the mouth, like the 

cuttle-fish (Cepkalopods) fig. 47. 

2. Those which creep on a flattened disc or foot, like 

snails ( Gasteropods} fig. 88, 89. 

3. Those which have no distinct head, and are enclosed 

in a bivalve shell, like the clams (Aceplidls). 

The CEPHALOPODS may be divided into 

a. The cuttle-fishes, properly so called (Teuthideans), 

fig. 47. 

b. Those having a shell, divided by sinuous partitions 

into numerous chambers (Ammonites), fig. 164. 


c. Those having a chambered shell with simple par- 
titions (Nautilus). 

The GASTEROPODS contain three orders : 

a. The land snails which breathe air (Pidmonates). 

b. The aquatic snails which breathe water (Branch' 

i/ers), fig. 88. 

c. Those which have wing-like appendages about the 

head, for swimming (Pteropods). 

The class of ACEPHALS contains three orders : 

a. Those having shells of two valves (bivalves), like 

the clam (Laniellibrancliiates). 
I. Those having two unequal valves, and furnished 

with peculiar arms (Brachiopods). 
c. Mollusks living in chains or clusters, like the Salpa, 

or upon plant-like stems, like Flustra (Bryozod), 

fig. 135. 

IV. The department of RADIATES is divided into three 
classes : 

1. Sea-urchins, bearing spines upon the surface (Echi- 

noderms), figs. 12, 26, 31. 

2. Jelly-fishes (Acaleylis), fig. 31. 

3. Polyps, fixed like plants, and with a series of flexi- 

ble arms around the mouth, figs. 48, 77, 143. 

The ECHINODERMS are divided into four orders : 

a. Sea-slugs, like biche-le-mar (Holothurians). 

b. Sea-urchins (Echini) fig. 26. 

c. Free star-fishes (Asteridce), fig. 17. 

d. Star-fishes mostly attached by a stem (Crinoids), 

fig. 150, 151. 

The ACALEPHS include the following orders : 

a. The Medusae, or common jelly fishes (Discophori'), 
figs. 31, 142. 


b. Those provided with aerial vesicles (Siphonophori). 

c. Those furnished with vibrating hairs, by which they 

move (Ctenophori). 

The class of POLYPS includes three orders. 

a. Fresh-water polyps, and similar marine forms (Hy- 
dro'ids), fig. 132. 

1). Marine polyps, like the sea-anemone and coral- 
polyp (Actinoids), figs. 48, 143. 

c. A still lower form, allied to the mollusks by their 
shell (Rhizopods). 

In addition to these, there are numberless kinds of micro- 
scopic animalcules, commonly called infusory animals (In- 
fusoria), from their being found specially abundant in water 
infused with vegetable matter. Indeed, a great many that 
were formerly supposed to be animals are now found to be 
vegetables. Others are ascertained to be crabs, mollusks, 
worms, &c. in their earliest stages of development. In 
general, however, they are exceedingly minute, and exhibit 
the simplest forms of animal life, and are now grouped 
together, under the title of Protozoa. But, as they are still 
very imperfectly understood, notwithstanding the beautiful 
researches already published on this subject, and as most 
of them, are likely to be finally distributed among vegeta- 
bles and the legitimate classes in the Animal Kingdom, we 
have not assigned any special place for them. 





1. ZOOLOGY is that department of Natural History which 
relates to Animals. 

2. The enumeration and naming of the animals which 
are found on the globe, the description of their forms, and 
the investigation of their habits and modes of life are the 
principal, but by no means the only objects of this science. 
Animals are worthy of our regard not only when considered 
as to the variety and elegance of their forms, or their 
adaptation to the supply of our wants ; but the Animal 
Kingdom, as a whole, has also a still higher signification. 
It is the exhibition of the divine thought, as it is carried out 
in one department of that grand whole which we call Na- 
ture ; and considered as such, it teaches us the most im- 
portant lessons. 

3. Man, in virtue of his twofold constitution, the spiritual 
and the material, is qualified to comprehend Nature. 



Having been made in the spiritual image of God, he is 
competent to rise to the conception of His plan and purpose 
in the works of Creation. Having also a material body, 
like that of animals, he is also prepared to understand the 
mechanism of organs, and to appreciate the necessities of 
matter, as well as the influence which it exerts over the in- 
tellectual element, throughout the whole domain of Nature. 

4. The spirit and preparation we bring to the study of 
Nature, is not a matter of indifference. When we would 
study with profit a work of literature, we first endeavor to 
make ourselves acquainted with the genius of the author ; 
and in order to know what end he had in view, we must 
have regard to his previous labors, and to the circumstances 
under which the work was executed. Without this, although 
we may perhaps enjoy the perfection of the whole, and ad- 
mire the beauty of its details, yet the spirit which pervades 
it will escape us, and many passages may even remain un- 

5. So, in the study of Nature, we may be astonished at 
the infinite variety of her products, and may even study 
some portion of her works with enthusiasm, and neverthe- 
less remain strangers to the spirit of the whole, ignorant of 
the plan on which it is based ; and may fail to acquire a 
proper conception of the varied affinities which combine 
beings together, so as to make of them that vast picture, in 
which each animal, each plant, each group, each class, has 
its place, and from which nothing could be removed without 
destroying the proper meaning of the whole. 

6. Besides the beings which inhabit the earth at the pre- 
sent time, this picture also embraces the extinct races which 
are now known to us by their fossil remains only. And 
these are of the greatest importance, since they furnish us 
with the means of ascertaining the changes and modifica- 
tions which the Animal Kingdom has undergone in the sue- 


cessive creations, since the first appearance of living 

7. It is but a short time since it was not difficult for a 
man to possess himself of the whole domain of positive 
knowledge in Zoology. A century ago, the number of 
known animals did not exceed 8000 ; that is to say, from 
the whole Animal Kingdom, fewer species were then 
known, than are now contained in many private collections 
of certain families of insects merely. At the present 
day, the number of living species which have been satisfac- 
torily made out and described, is more than 50,000.* The 
fossils already described exceed 6000 species ; and if we 

* The number of vertebrate animals may be estimated at 20,000. 
About 1500 species of mammals are pretty precisely known, and the num- 
ber may probably be carried to about 2000. 

The number of Birds well known is 4 or 5000 species, and the probable 
number is 6000. 

The Reptiles number about the same as the Mammals, 1500 described 
species, and they will probably reach the number of 2000. 

The Fishes are more numerous ; there are from 5 to 6000 species in the 
museums of Europe, and the number may probably amount to 8 or 10,000. 

The number of Mollusks already in collections, probably reaches 8 or 
10,000. There are collections of marine shells, bivalve and univalve, which 
amount to 5 or 6000 ; and collections of land and fluviatile shells, which 
count as many as 2000. The total number of inollusks would therefore 
probably exceed 15,000 species. 

Among the articulated animals it is difficult to estimate the number of 
species. There are collections of coleopterous insects which number 20 to 
25,000 species ; and it is quite probable, that by uniting the principal col- 
lections of insects, 60 or 80,000 species might now be counted ; for the 
whole department of articulata, comprising the Crustacea, the cirrhipeda, 
the insects, the red-blooded worms, the intestinal worms, and the infuso- 
ria, as far as they belong to this department, the number would already 
amount to 100,000 ; and we might safely compute the probable number of 
species actually existing, at double that sum. 

Add to these about 10,000 for radiata, echini, star-fishes, medusae, and 
polypi, and we have about 250,000 species of living animals ; and suppos- 
ing the number of fossil species only to equal them, we have, at a very 
moderate computation, half a million of species. 


consider that wherever any one stratum of the earth has 
been well explored, the number of species discovered has 
not fallen below that of the living species which now inhabit 
any particular locality of equal extent, and then bear in 
mind that there is a great number of geological strata, we 
may anticipate the day when the ascertained fossil species 
will far exceed the living species.* 

8. These numbers, far from discouraging, should, on the 
contrary, encourage those who study Natural History. 
Each new species is, in some respects, a radiating point 
which throws additional light on all around it ; so that as 
the picture is enlarged, it at the same time becomes more 
intelligible to those who are competent to seize its promi- 
nent traits. 

9. To give a detailed account of each and all of these 
animals, and to show their relations to each other, is the 
task of the Naturalist. The number and extent of the vol- 
umes already published upon the various departments of 
Natural History show, that only a mere outline of a domain 
so vast could be fully sketched in an elementary work, and 
that none but those who make it their special study can be 
expected to survey its individual parts. 

10. Every well-educated person, however, is expected to 
have a general acquaintance with the great natural phe- 
nomena constantly displayed before his eyes. There is a 
general knowledge of man and the subordinate animals, 
embracing their structure, races, habits, distribution, mutual 
relations, &c., which is calculated not only to conduce es- 

* In a separate work, entitled " Nomenclator Zodlogicus^ by L. Agas- 
siz, the principles of nomenclature are discussed, and a list of the names of 
genera and families proposed by authors is given. To this work those are 
referred who may desire to become more familiar with nomenclature, and 
to know in detail the genera and families in each class of the Animal 


sentially to our happiness, but which it would be quite inex- 
cusable to neglect. This general view of Zoology, it is the 
purpose of this work to afford. 

11. A sketch of this nature should render prominent the 
more general features of animal life, and delineate the ar- 
rangement of the species according to their most natural 
relations and their rank in the scale of being ; and thus 
give a panorama, as it were, of the entire Animal Kingdom. 
To accomplish this, we are at once involved in the question, 
what is it that gives an animal precedence in rank ? 

12. In one sense, all animals are equally perfect. Each 
species has its definite sphere of action, whether more or 
less extended, its own peculiar office in the economy of 
nature ; and it is perfectly adapted to fulfil all the purposes 
of its creation, beyond the possibility of improvement. In 
this sense, every animal is perfect. But there is a wide 
difference among them, in respect to their organization. In 
some it is very simple, and very limited in its operation ; in 
others, extremely complicated, and capable of exercising a 
great variety of functions. 

13. In this physiological point of view, an animal may be 
said to be more perfect in proportion as its relations with 
the external world are more varied ; in other words, the 
more numerous its functions are. Thus, an animal, like a 
quadruped, or a bird, which has the five senses fully deve- 
loped, and which has, moreover, the faculty of readily 
transporting itself from place to place, is more perfect than 
a snail, whose senses are very obtuse, and whose motion is 
very sluggish. 

14. In like manner, each of the organs, when separately 
considered, is found to have every degree of complication, 
and, consequently, every degree of nicety in the perform- 
ance of its function. Thus, the eye-spots of the star-fish 
and jelly-fish, probably are endowed with merely the fac- 



ulty of perceiving light, without the power of distinguishing 
objects. The keen eye of the bird, on the contrary, dis- 
cerns minute objects at a great distance, and when com- 
pared with the eye of a fly, is found to be not only more 
complicated, but constructed on an entirely different plan. 
It is the same with every other organ. 

15. We understand the faculties of animals, and appre- 
ciate their value, just in proportion as we become ac- 
quainted with the instruments which execute them. The 
study of the functions or uses of organs therefore requires 
an examination of their structure ; they must never be dis- 
joined, and must precede the systematic distribution of ani- 
mals into classes, families, genera, and species. 

16. In this general view of organization, we must ever 
bear in mind the necessity of carefully distinguishing be- 
tween affinities and analogies, a fundamental principle re- 
cognized even by Aristotle, the founder of scientific Zoology. 
Analogy or liomology is the relation between organs or parts 
of the body which are constructed on the same plan, how- 
ever much they vary in form, but which serve for very dif- 
ferent uses. Analogy, on the contrary, indicates the simi- 
larity of purposes or functions performed by organs of dif- 
ferent structure. 

17. Thus, there is an analogy between the wing of a bird 
and that of a butterfly, since both of them serve for flight. 
But there is no affinity between them, since, as we shall here- 
after see, they differ totally in their anatomical relations. On 
the other hand, there is an affinity between the bird's wing 
and the hand of a monkey, since, although they serve for dif- 
ferent purposes, the one for climbing, and the other for flight, 
yet they are constructed on the same plan. Accordingly, 
the bird is more nearly allied to the monkey than to the 
butterfly, though it has the faculty of flight in common with 
the latter. Affinities, and not analogies, therefore, must 
guide us in the arrangement of animals. 


18. Our investigations should not be limited to adult 
animals, but the changes which they undergo during the 
whole course of their development must also be considered. 
Otherwise, we shall be liable to exaggerate the importance 
of certain peculiarities of structure which have a predomi- 
nant character in the full-grown animal, but which are 
shaded off, and vanish, as we revert to the earlier periods of 

19. Thus, for example, by regarding only adult individu- 
als, we might be induced to divide all animals into two 
groups, according to their mode of respiration ; uniting, on 
the one hand, all those which breathe by gills, and, on the 
other, those which breathe by lungs. But this distinction 
loses its importance, when we consider that various animals, 
for example, frogs, which respire by lungs in the adult 
state, have only gills when young. It is thence evident that 
the respiratory organs cannot be taken as a satisfactory 
basis of our fundamental classification. They are, as we 
shall see, subordinate to a more important organism, namely, 
the nervous system. 

20. Again, we have a means of appreciating the relative 
grade of animals by the comparative study of their devel- 
opment. It is evident that the caterpillar, in becoming a 
butterfly, passes from a lower to a higher state. Clearly, 
therefore, animals resembling the caterpillar, the worms, 
for instance, must occupy a lower rank than those approach- 
ing the butterfly, like most insects. There is no animal 
which does not undergo a series of changes similar to those 
of the caterpillar or the chicken ; only, in many of them, 
the most important ones occur before birth, during what is 
called the embryonic period. 

21. The life of the chicken has not just commenced when 
it issues from the egg ; for if we break the egg some days 
previous to the time of hatching, we find in it a living ani- 


mal, which, although imperfect, is nevertheless a chicken ; 
it has been developed from a hen's egg, and we know that, 
should it continue to live, it would infallibly display all the 
characteristics of the parent bird. Now, if there existed in 
Nature an adult bird as imperfectly organized as the 
chicken on the day, or the day before it was hatched, we 
should assign to it an inferior rank. 

22. In studying the embryonic states of the mollusks or 
worms, we observe in them points of resemblance to many 
animals of a lower grade, and to which they at length be- 
come entirely dissimilar. For example, the myriads of 
minute aquatic animals embraced under the name of Infu- 
soria, in their organization generally, very simple, remind 
us of the embryonic forms of other animals. We shall have 
occasion to show that the Infusoria are not to be considered 
as a distinct class of animals, but that among them are 
found members of all the lower classes of animals, mollusks, 
crustaceans, polyps, and many of them are even found to 
belong to the Vegetable Kingdom. 

23. Not less striking are the relations that exist between 
animals and the regions they inhabit. Every animal has its 
home. Animals of the cold regions are not the same as 
those of temperate climates ; and these latter, in their turn, 
differ from those of tropical regions. Certainly, no one will 
maintain it to be the effect of accident that the monkeys, 
the most perfect of all brute animals, are found only in hot 
countries ; or that it is by chance that the white-bear and 
reindeer inhabit only cold regions. 

24. Nor is it by chance that the largest of all animals, 
of every class, the whales, the aquatic birds, the sea-turtles, 
dwell in the water rather than on the land. And while the 
water affords freedom of motion to the largest, so is it also 
the home of the smallest of living things, affording to them 
a freedom from obstacles to their motion, which they could 
not enjoy elsewhere. 


25. Nor are our researches to be limited to the animals 
now living. There are buried in the crust of the earth the 
remains of a great number of animals belonging to species 
which do not exist at the present day. Many of these re- 
mains present forms so extraordinary that it is almost im- 
possible to trace their connection with any animals now 
living. In general, they bear a striking analogy to the em- 
bryonic forms of existing species. For example, the curi- 
ous fossils known under the name of Trilobites (Fig. 156), 
have a shape so singular that it might well be doubted to 
what group of articulated animals they belong. But if we 
compare them with the embryo crab, we find so remarkable 
a resemblance that we hesitate not to refer them to the 
crustaceans. We shall also see that some of the Fishes of 
ancient epochs present shapes entirely peculiar to them- 
selves (Fig. 157), but resembling in a striking manner, the 
embryonic forms of our common fishes. A determination 
of the successive appearance of animals in the order of 
time is therefore of much importance in assisting to deter- 
mine the relative rank of animals. 

26. Besides the distinctions to be derived from the varied 
structure of organs, there are others less subject to rigid 
analysis, but no less decisive, to be drawn from the imma- 
terial principle, with which every animal is endowed. It is 
this which determines the constancy of species from gene- 
ration to generation, and which is the source of all the va- 
ried exhibitions of instinct and intelligence which we see 
displayed, from the simple impulse to receive the food which 
is brought within their reach, as observed in the polyps, 
through the higher manifestations, in the cunning fox, the 
sagacious elephant, the faithful dog, and the exalted intel- 
lect of man, which is capable of indefinite expansion. 

27. Such are some of the general aspects in which we 
are to contemplate the animal creation. Two points of 


view should never be lost sight of, or disconnected, namely, 
the animal in respect to its own organism, and the animal 
in its relations to creation as a whole. By adopting too ex- 
clusively either of these points of view, we are in danger of 
falling either into gross materialism, or into vague and 
profitless pantheism. He who beholds in Nature nothing 
besides organs and their functions, may persuade himself 
that the animal is merely a combination of chemical and 
mechanical actions and reactions, and thus becomes a mate- 

28. On the contrary, he who considers only the mani- 
festations of intelligence and of creative will, without taking 
into account the means by which they are executed, and 
the physical laws by virtue of which all beings preserve 
their characteristics, will be very likely to confound the 
Creator with the creature. 

29. It is only as it contemplates, at the same time, matter 
and mind, that Natural History arises to its true character 
and dignity, and leads to its worthiest end, by indicating to 
us, in Creation, the execution of a plan fully matured in the 
beginning, and invariably pursued ; the work of a God infi- 
nitely wise, regulating Nature according to immutable laws, 
which He has himself imposed on her. 





30. NATURAL HISTORY, in its broadest sense, embraces 
the study of all the bodies which compose the crust of the 
earth, or which are dispersed over its surface. 

31. These bodies may be divided into two great groups ; 
inorganic bodies (minerals and rocks), and living or organ- 
ized bodies (vegetables and animals). These two groups 
have nothing in common, save the universal properties of 
matter, such as weight, color, &c. They differ at the same 
time, as to their form, their structure, their composition, and 
their mode of existence. 

32. The distinctive characteristic of inorganic bodies, is 
rest ; the distinctive trait of organized bodies, is independ- 
ent motion, LIFE. The rock or the crystal, once formed, 
never changes ; their constituent parts or molecules invari- 
ably preserve the position which they have once taken in 
respect to each other. Organized bodies, on the contrary, 
are continually in action. The sap circulates in the tree, 
the blood flows through the animal, and in both there is, 


besides, the incessant movement of growth, decomposition, 
and renovation. 

33. Their mode of formation is also entirely different. 
They are, in the first place, derived from sources unlike 
themselves ; and if a mineral is enlarged, it is simply by 
the outward addition of particles constituted like itself. 
Organized bodies are not formed in this manner. They 
always, and necessarily, are derived from beings similar 
to themselves ; and once formed, they increase always 
from within outward, by the interposition of new particles, 
which go to complete the individual. 

34. Finally, organized bodies are limited in their dura- 
tion. Animals and plants are constantly losing some of 
their parts by decomposition during life, which at length 
cease to be supplied, and they die, after having lived for a 
longer or shorter period. Inorganic bodies, on the con- 
trary, contain within themselves no principle of destruction ; 
and unless subjected to some foreign influence, a crystal or 
a rock would never change. The limestone and granite of 
our mountains remain just as they were formed in ancient 
geological epochs ; while numberless generations of plants 
and animals have lived and perished upon their surface. 



35. The exercise of the functions of life, which is the es- 
sential characteristic of organized bodies (32), requires a 
degree of flexibility of the organs. This is secured by 
means of a certain quantity of watery fluid, which pene- 


trates all parts of the body, and forms one of its principal 

36. All living bodies, without exception, are made up of 
tissues so constructed as to be permeable to liquids. There 
is no part of the body, no organ, however hard and compact 
it may appear, which has not this peculiar property. It ex- 
ists in the bones of animals, as well as in their flesh and fat ; 
in the most solid wood, as well as in the bark and flowers 
of plants. It is to this general structure that the term or- 
ganism is now applied. Hence the collective name of 
organized beings* which includes both the animal and the 
vegetable kingdoms. 

37. The vegetable tissues and most of the organic struc- 

tures, when examined by the microscope, 
in their early states of growth, are found 
to be composed of hollow vesicles or cells. 
The natural form of the cells is that of a 
sphere or of an ellipsoid, as may be easily 
seen in many plants ; for example, in the 

/ V A / tissue of the house-leek (Fig. 1). The 

in, ^ ^v_y ' 

Fig. i. intervals which sometimes separate them 

from each other, are called intercellular passages or spaces 
(w). When the cellules are very numerous, and crowd 
each other, their outlines become angular, and the intercel- 

* Formerly, animals and plants were said to be organized because they 
are furnished with definite parts, called organs^ which execute particular 
functions. Thus, animals have a stomach, a heart, lungs, &c. ; plants 
have leaves, petals, stamens, pistils, roots, &c., all of which are indispen- 
sable to the maintenance of life, and the perpetuation of the species. Since 
the discovery of the identity of the structure of animal and vegetable tis- 
sues, a common denomination for this uniformity of texture, has been 
justly preferred ; and the existence of tissues is now regarded as the basis 
of organization. 



lular spaces disappear, as seen in figure 2, which represents 

the pith of the elder. They then 
have the form of a honey-comb ; 
whence they have derived their 
name of cellules. 

38. All the organic tissues, whether 
animal or vegetable, originate from 
the cell. The cell is to the organ- 
ized body what the primary form of the crystal is to the 
secondary, in minerals. As a general fact, it may be stated 
that animal cells, are smaller than vegetable a b 

cells, and contain a central dot or vesicle, called (S tjfe\ 
nucleus. Hence those cells are called nucle- 
ated cells (Fig. 3, a). Sometimes the nucleus Fig. 3. 
itself contains a still smaller dot, called nucleolus (Z>). 

39. The elementary structure of vegetables is easily ob- 
served in every part of a plant, and its cellular character 
has been long known. But with the animal tissues there is 
far greater difficulty. Their variations are so great, and 
their transformations so diverse, that after the embryonic 
period it is often difficult, even by the closest examination, 
to detect their original structure. 

40. Several kinds of tissues have been designated in the 
animal structure ; but their differences are not always well 
marked, and they pass into each other by insensible shades. 
Their modifications are still a matter of investigation, and 
we refer only to the most important distinctions. 

41. The areolar tissue. It is the most generally diffused. 
The cells are usually large, but irregular, with their walls 
often imperfect. In man, as well as in the higher animals, 
it is interposed, in layers of various thickness, between the 
organs of the body, and contains more or less fat. Most of 
the membranes are mere modifications of it. 

42. The cartilaginous tissue is composed of nucleated 


cells, the intercellular spaces being filled with a more com- 
pact substance called the hyaline matter. Figure 4 repre- 
sents a slip of cartilage from a horse, under 
a magnifying power of one hundred and twen- 
ty diameters. 

43. The osseous or l>ony tissue differs from 
the cartilaginous tissue, in having the meshes 
filled with salts of lime, instead of hyaline sub- 

Fig. 4. 

stance, whence its compact and solid appearance. It con- 
tains, besides, minute, rounded, or star-like 
points, improperly called bone-corpuscles, 
which are found to be cavities or canals, and 
^iBO'iis -^r are some ti mes fancifully branched, as is seen 
^^^^M^^U m fig ure 5? representing the section of a horse 
bone, magnified four hundred and fifty times. 

44. The muscular tissue, which forms the flesh of ani- 
mals, is composed of bundles of parallel fibres, which, in the 
muscles under the control of the will, are commonly crossed 
by very fine lines or wrinkles, and possess the peculiar 
property of contracting or shortening themselves, under the 
influence of the nerves. Every one is sufficiently familiar 
with this tissue, in the form of lean meat. 

45. The nervous tissue is of different kinds. In the 

nerves proper, it is composed of 
very delicate fibres, which return 
back at their extremities, and form 
loops, as shown in figure 7, repre- 
senting nervous threads, as they pig. 7. 
terminate in the skin of a frog. The same fibrous 
structure is found in the white portion of the brain. 
But the gray substance is composed of very minute granu- 
lations, with larger cells, collected in clusters, as seen in 
figure 8. 

46. The tissues above enumerated differ from each other 



more widely, in proportion as they are examined in animals 
of a higher rank. As we descend in the scale of being, 
the differences become gradually effaced. The soft body 
of a snail is much more uniform in its composition, than 
the body of a bird, or a quadruped. Indeed, multitudes of 
animals are known, made up of nothing but cells in contact 
with each other. Such is the case with most of the Infu- 
soria, which nevertheless live and move most freely, by 
means of little hair-like organs at their surface, that are 
themselves merely modified cells. 

47. A no less remarkable uniformity of structure is to be 
observed in the higher animals, in the earlier periods of 
their existence, before the body has arrived at its definite 
form. The head of the adult salmon, for instance, con- 
tains all the tissues we have mentioned, namely, bone, 

cartilage, muscle, nerve, brain, 
vessels, and membranes. But let 
us examine it during the embry- 
onic state, that is, while it is yet in 
the egg, and we find that the whole 
Fig. 3- head is made up of cells which dif- 

fer merely in their dimensions ; those at the top of the head 
being very small, those surrounding the eye a little larger, 
and those beneath being still larger. It is only at a later 
period, after still further development, that these cellules 
become transformed, some of them into bone, others into 
blood, others into flesh, &c. 

48. Again, the growth of the body, the introduction of 
various tissues, the change of form and structure, proceed in 
such a manner as to give rise to several cavities, variously 
combined among themselves, and each containing, at the 
end of these transformations, peculiar organs, or peculiar 
systems of organs. 




49. At first thought, nothing would seem more widely 
different than animals and plants. What is there in com- 
mon, for instance, between an oak or an elm, and the bird 
which seeks shelter under their foliage ? 

50. The differences are usually so obvious, that this 
question would be superfluous had we to apply it to only the 
higher forms of the two kingdoms. But this contrast di- 
minishes, in proportion as their construction is simplified ; 
and *as we descend to the lower forms, the distinctions 
are so few and so feebly characterized, that it becomes 
at length difficult to pronounce whether the object we have 
before us is an animal or a plant. Thus the sponges have 
so great a resemblance to some of the polypi, that they have 
generally been classed among animals, although in reality 
they belong to the vegetable kingdom. 

51. Animals and plants differ in the relative predomi- 
nance of the elements, oxygen, carbon, hydrogen and nitro- 
gen, of which they are composed. In vegetables, only a 
trace of nitrogen is found, and that merely in the seeds, and 
some other products of the plant ; while it enters largely 
into the composition of the animal tissues. 

52. Another peculiarity of the Animal Kingdom is, the 
presence of large, distinctly limited cavities, destined for 
the lodgment of certain organs ; such is the skull and 
the chest in the higher animals, the cavity of the gills in 
fishes, and of the abdomen or general cavity of the body, 
for the reception of the digestive organs, which exists in all 
animals, without exception. 



53. The well-defined and compact forms of the organs 
lodged in these cavities, is also another peculiarity of ani- 
mals. In plants, the organs designed for special purposes 
are not embodied into one mass, but are distributed over 
various parts of the individual. Thus, the leaves, which 
answer to the lungs, instead of being condensed into one 
organ, are scattered in countless numbers over the branches. 
Nor is there any one organ corresponding to the brain, the 
heart, the liver, or the stomach. 

54. Moreover, the presence of a proper digestive cavity, 
involves marked differences between the two kingdoms, in 
respect to alimentation or the use of food. In plants, the 
fluids absorbed by the roots are carried, through the trunk 
and all the branches, to the whole plant, before they arrive 
at the leaves, where they are to be digested. In animals, 
on the contrary, the food is at once received into the digest- 
ive cavity, where it is elaborated ; and it is only after it has 
been thus dissolved and prepared, that it is introduced into 
the other parts of the body. 

55. Plants commence their development from a single 
point, the seed, and, in like manner, all animals are deve- 
loped from the egg. But the animal germ is the result of 
successive transformations of the yolk, while nothing similar 
takes place in the plant. The subsequent development of 
individuals is also different in the two kingdoms. No limit 
is placed to the increase of plants ; trees put out new 
branches and new roots as long as they live. Animals, on 
the contrary, have all a limited size and figure ; and these 
once attained, the subsequent changes are accomplished 
without any increase of volume or essential alteration of 
form ; while the appearance of vegetables is frequently 
modified, in a notable manner, by the development of new 

56. In the effects they produce upon the air, by respira- 


tion, there is an important difference. Animals consume 
the oxygen, and give out carbonic acid gas which is de- 
structive to animal life ; while plants, by respiration, which 
they, in most instances, perform by means of the leaves, 
reverse the process, and thus furnish oxygen, which is so 
essential to animals. If an animal be confined in a small 
portion of air, or water containing air, this soon becomes so 
vitiated by respiration as to be unfit to sustain life ; but if 
living plants are confined with the animal at the same time, 
the air is maintained pure, and no difficulty is experienced. 
The practical effect of this compensation, in the economy of 
Nature, is obviously most important ; vegetation restoring 
to the atmosphere what is consumed by animal respiration, 
combustion, &c., and vice versa. 

57. But there are two things which, more than all others, 
distinguish the animal from the plant, namely, the power of 
moving itself or its parts at will, and the power of perceiv- 
ing other objects or their influences ; in other words, volun- 
tary motion and sensation. 

58. All animals are susceptible of undergoing pleasure 
and pain. Plants have also a certain sensibility. They 
wither and fade under a burning sun, or when deprived of 
moisture ; and they die when subjected to too great a de- 
gree of cold, or to the action of poisons. But they have no 
consciousness of these influences, and suffer no pain ; while 
animals under similar circumstances suffer. Hence they 
have been called animate beings, in opposition to plants, 
which are inanimate beings. 





59. LIFE, in animals, is manifested by two sorts of func- 
tions, viz. : First, the peculiar functions of animal life, or 
those of relation, which include the functions of sensation 
and voluntary motion ; those which enable us to approach, 
and perceive our fellow beings and the objects about us, and 
to bring us into relation with them : Second, the functions 
of vegetative life, which are nutrition and reproduction ; * 
those indeed, which are essential to the maintenance and 
perpetuation of life. 

60. The two distinguishing characteristics of animals, 
namely, motion and sensation (57), depend upon a special 
apparatus, which is wanting in plants, and which is called 
the nervous system. The nervous system, therefore, is the 

* This distinction is the more important, inasmuch as the organs of 
animal life, and those of vegetative life, spring from very distinct layers of 
the embryonic membrane. The first are developed from the upper layer, 
and the second from the lower layer of the germ of the animal. Sec 
Chapter on Embryology, p. 112. 



part characteristic of the animal body. It is the grand cen- 
tre from which all the commands of the will issue, and to 
which all sensations tend. 

61. Greatly as the form, the arrangement, and the vol- 

ume of the nervous system 
vary in different animals, 
they may all be reduced to 
four principal types, which 
correspond moreover, to the 
four great departments of the 
Animal Kingdom. In the 
vertebrate animals, namely, 
the fishes, reptiles, birds, and 
mammals, the nervous sys- 
tem is composed of two prin- 
cipal masses, the spinal mar- 
row (Fig. 9, c), which runs 
along the back, and the 
brain, contained within the 
skull.* The volume of the 
brain is proportionally larger, 
as the animal occupies a 
more elevated rank in the 
scale of being. Man, who 
stands at the head of Crea- 
tion, is in this respect also, the 
9 most highly endowed being. 

62. The brain and spinal marrow give origin to the 
nerves, which are distributed, in the form of branching 
threads, through every part of the body. The branches 

* The brain is composed of several distinct parts which vary greatly, in 
their relative proportions, in different animals, as will appear hereafter. 
They are: 1. The medulla oblongata ; 2. Cerebellum; 3. Optic lobes; 
4. Cerebral hemispheres ; 5. Olfactory lobes. See figures 9 and 21. 


which arise from the brain are twelve pairs, called the cere- 
bral nerves, and are chiefly destined for the organs of sense 
located in the head. Those which arise from the spinal 
marrow are also in pairs, one pair for each vertebra or 
joint of the back. The number of pairs varies, therefore, in 
different classes and families, according to the number of 
vertebra?. Each nerve is double, in fact, being composed 
of two threads, which spring from the spinal marrow by 
separate roots, and accompany each other throughout their 
whole course. One of these transmits the commands of the 
will, which produce motion ; the other receives and conveys 
impressions to the brain, and produces sensations. 

63. In the Articulated animals, comprising the crabs, 
barnacles, worms, spi- 
ders, insects, and oth- 
er animals formed of 

rings, the nervous sys- 
tem consists of a se- Fig. 10. 
ries of small centres or swellings, called ganglions (Fig. 10), 
placed beneath the alimentary canal, on the floor of the gen- 
eral cavity of the body, and connected by threads ; and of a 
more considerable mass placed above the oesophagus or 
throat, connected with the lower ganglions by threads which 
form a collar around the alimentary canal. The number of 
ganglions generally corresponds to the number of rings. 

64. In the Mollusks (Fig. 11), the nervous system con- 

sists of a single ganglionic 
circle, the principal swell- 
ings of which are placed 
symmetrically above and 
below the oesophagus, and 
from whence the filaments, 
Fig. 11. which supply the organs 

in different directions, take their origin. 



65. In the Radiata (Fig. 12), the nervous system is re- 
duced to a single ring, encircling 
the mouth. It differs essentially 
from that of the Mollusks, by be- 
ing disposed in a horizontal posi- 
tion, and by its star-like form. 

66. The nerves branch off and 
diffuse sensibility to every portion 
of the body, and thereby men and 
the higher animals are enabled to 
Fig. 12. gain a knowledge of the general 

properties of the objects which surround them ; every point 
of the body being made capable of determining whether 
an object is hot or cold, dry or moist, hard or soft. There 
are some parts, however, the ends of the fingers, for exam- 
ple, in which this sensibility is especially acute, and these 
also receive a larger supply of nerves. 

67. On the contrary, those parts which are destitute of 
sensibility, such as the feathers of birds, the wool of ani- 
mals, or the hair of man, are likewise destitute of nerves. 
But the conclusive proof that sensibility resides in the 
nerves is, that when the nerve which supplies any member 
of the body is severed, that member at once becomes insen- 

68. There are animals in which the faculty of percep- 
tion is limited to this general sensation ; but their number is 
small, and in general, they occupy the lowest place in the 
series. Most animals, in addition to the general sensibility, 
are endowed with peculiar organs for certain kinds of per- 
ceptions, which are called the SENSES. These are five in 
number, namely : sight, hearing, smell, taste, and touch. 



1. Of Sight. 

69. SIGHT is the sense by which light is perceived, and 
by means of which, the form, dimensions, position, color 
and brilliancy of surrounding objects, are discerned. Some 
of these properties maybe also ascertained, though in a less 
perfect manner, by the sense of touch. We may obtain an 
idea of the size and shape of an object, by handling it ; but 
the properties that have a relation to light, such as color and 
brilliancy, and also the form and size of borh^s that are be- 
yond our reach, are exclusively recognized by sight. 

70. The EYE is the organ of vision. The number, struc- 
ture, and position of the eyes in the body, is considerably 
varied in the different classes. But whatever may be their 
position, these organs are always in connection with particu- 
lar nerves, called the optic nerves (Fig. 13, .). In the ver- 
tebrates, these constitute the second pair of the cerebral 
nerves, and arise directly from the middle mass of the 
brain (Fig. 21, Z>), which, in the embryo, is the most con- 
siderable of all. 

71. Throughout the whole series of vertebrate animals, 
the eyes are only two in num- 
ber, and occupy bony cavities 

of the skull, called the orbits. 
The organ is a globe or hollow 
sphere, formed by three mem- 
branes enclosed one within the 
other, and filled with transpa- 
rent matter. Figure 13 repre- 
sents a vertical section through Fi 
the eye, and will give an idea of the relative position of 
these different parts. 


72. The outer coat is called the sclerotic (Z>) ; it is a thick, 
firm, white membrane, having its anterior portion transpa- 
rent. This transparent segment, which seems set in the 
opaque portion, like a watch-glass in its rim, is called the 
cornea (f). 

73. The inside of the sclerotic, is lined by a thin, dark 
colored membrane, the choroid (c). It becomes detached 
from the sclerotic, when it reaches the edge of the cornea, 
and forms a curtain behind it. This curtain gives to the eye 
its peculiar color, and is called the iris (g). The iris readily 
contracts and dilates, so as to enlarge or diminish an 
opening at its centre, the pupil, according as more or 
less light is desired. Sometimes the pupil is circular, as 
in man, the dog, the monkey ; sometimes in the form of a 
vertical ellipse, as in the cat ; or, it is elongated sidewise as 
in the sheep. 

74. The third membrane is the retina (d). It is formed by 
the optic nerve, which enters the back part of the eye, by 
an opening through both the sclerotic and choroid coats, and 
expands upon the interior into a whitish and most delicate 
membrane. It is upon the retina that the images of ob- 
jects are received, and produce impressions, which are con- 
veyed by the nerve to the brain. 

75. The fluids which occupy the cavity of the eye, are of 
different densities. Behind, and directly opposite to the 
pupil, is placed a spheroidal body, called the crystalline 
lens (e). It is tolerably firm, perfectly transparent, and com- 
posed of layers of unequal density, the interior being 
always more compact than the exterior. Its form varies in 
different classes of animals. In general, it is more convex 
in aquatic than in land animals ; whilst with the cornea, it is 
directly the contrary, being flat in the former, and con- 
vex in the latter. 

76. By means of the iris ; the cavity in front of the crys- 



talline is divided into two compartments, called the anterior 
and posterior chambers (i). The fluid which fills these 
chambers is a clear watery liquid, called the aqueous 
humor. The portion of the globe behind the lens, which is 
much the largest, is filled by a gelatinous liquid, perfectly 
transparent, like that of the chambers, but somewhat more 
dense. This is called the vitreous humor (h). 

77. The object of this apparatus is to receive the rays of 
light, which diverge from all points of bodies placed before 
it, and to bring them to a point again upon the retina. 
It is a well-known fact, that when a ray of light passes 
obliquely from one medium to another of different density, 
it will be refracted or turned out of its course more or 
less, according to the difference of this density, and the ob- 
liquity at which the ray strikes the surface. This may 
be illustrated by the following figure. (Fig. 14). 

A/ E 

Fig. 14. 

The ray a c, which strikes the cornea A B perpendicularly, 
continues without deviation, until it reaches the bottom of 
the eye at c. But the rays am and an, which strike the eye 
obliquely, change their direction, and instead of proceeding 
onward to mg and nd, take the direction mi and nf. A 
still further refraction, though less considerable, is occa- 
sioned by passing through the crystalline lens C D, and the 
vitreous humor, so that the tw r o rays m i and nf, will at last 
meet in a point. This point is called the focus (c), and in 
distinct vision, is always precisely at the retina, E F. 

78. From this arrangement, the image found upon the 


retina, will be inverted. We may satisfy ourselves of this 
by direct observation. The eye of the white rabbit being 
destitute of the black pigment of the choroid, is quite trans- 
parent. Take the eye, soon after the death of the animal, 
and arrange it in one end of a tube, so that the cornea will 
look outwards ; then if we look through from the other end 
of the tube, we may see objects to which it is directed exactly 
pictured upon the retina, but in a reversed position. 

79. The mechanical structure of the eye, may be per- 
fectly imitated by art. Indeed, the camera obscura is an 
instrument constructed on the very same plan. By it, exter- 
nal objects are pictured upon a screen, placed at the bottom 
of the instrument, behind a magnifying lens. The screen 
represents the retina ; the dark walls of the instrument 
represent the choroid ; and the cornea, the crystalline and 
the vitreous humor combined, are represented by the mag- 
nifying lens. But there is this important difference, that 
the eye has the power of changing its form, and of adapt- 
ing it so as to discern with equal precision, very remote, 
as well as very near objects. 

SO. By means of muscles which are attached to the ball, 
the eyes may be rolled in every direction, so as to view ob- 
jects on all sides, without moving the head. The eyes are 
usually protected by lids, which are two in the mammals, 
and generally furnished with a range of hairs at their edges, 
called eye-lashes. The birds have a third lid, which is ver- 
tical, and is also found in most of the reptiles and a few 
mammals. In fishes, the lids are wanting, or immovable. 

81. The eye constructed as above described, is called a 
simple eye, and belongs more especially to the vertebrate 
animals. In man, it arrives at its highest perfection. In 
him, the eye also performs a more exalted office than mere 
vision. It is a mirror in which the inner man is reflected. 
His passions, his joys, and his sorrows, his inmost self, are 


reflected, with the utmost fidelity, in the expression of his 
eye, and it has been rightly called " the window of the 

82. Many of the invertebrate animals, have the eyes 
constructed upon the same plan as that of the vertebrate 
animals, but with this essential difference, that the optic 
nerve which forms the retina, is not derived from a ner- 
vous centre, analogous to the brain, but arises from one 
of the ganglions. Thus, the eyes of the cuttle-fish contain 
all the parts essential to the eye of the superior ani- 
mals, and what is no less important, they are only two in 
number, placed upon the sides of the head. 

83. The snail, and kindred animals 
have, in like manner, only two eyes, 
mounted on the tip of a long stalk, 
(the tentacle), or situated at its base, 
or on a short pedestal by its side. 
Fig. 15. Their structure is less perfect than 

the eyes of the cuttle-fish, but still there is a crystalline, 
and more or less distinct traces of the vitreous body. 
Some bivalve mollusks, the scollops for example, have 
likewise a crystalline, but instead of two, they are fur- 
nished with numerous eyes, which are arranged like a bor- 
der around the lower margin of the animal. 

84. In spiders, the eyes 
are likewise simple, and 
usually eight in number. 
These little organs, usu- 
ally called ocelli, instead 
of being placed on the 
sides of the body or of the 
head, occupy the anterior Fig. 16. 

part of the back. All the essential parts of a simple eye, 
the cornea, the crystalline, the vitreous body, are found in 


them, and even the choroid, which presents itself in the 
form of a black ring around the crystalline. Many insects, 
in their caterpillar state, also have simple eyes. 

85. Rudiments of eyes have been observed in very 
many of the worms. They generally appear as small 
black spots on the head ; such as are seen on the head 
of the Leech, the Planaria and the Nereis. In these latter 
animals there are four spots. According to Mialler, they 
are small bodies, rounded behind, and flattened in front, 
composed of a black, cup-shaped membrane, containing a 
small white, opaque body, which seems to be a continuation 
of the optic nerve. It cannot be doubted, therefore, that 
these are eyes ; but as they lack the optical apparatus 
which produces images, we must suppose that they can only 
receive a general impression of light, without the power of 
discerning objects. 

86. Eye-spots very similar 
to those of the Nereis, are 
found at the extremity of the 
rays of some of the star-fishes, 
in the sea-urchins, at the mar- M 
gin of many Medusae, and in 
some Polypi. M. Ehrenberg 
has shown that they also exist 
in a large number of the Infu- 
soria. Fig 17> 

87. In all the animals already mentioned, the eyes, what- 
ever their number, are apart from each other. But there is 
still another type of simple eyes, known as aggregate eyes. 
In some of the millipedes, the pill-bugs, for instance, the 
eyes are collected into groups, like those of spiders ; each 
eye inclosing a crystalline and a vitreous body, surrounded 
by a retina and choroid. Such eyes consequently form a 




natural transition to the compound eyes of insects, to which 
we now give our attention. 

88. Compound eyes have the same general form as 
simple eyes ; they are placed either on the sides of the head, 
as in insects, or supported on pedestals, as in the crabs. 
But if we examine an eye of this kind by a magnifying lens, 
we find its surface to be composed of an infinite number of 
angular, usually six-sided faces. If these fa9ettes are re- 
moved, we find beneath, a corresponding number of cones (c), 
side by side, five or six times as long as they are broad, 
and arranged like rays around the optic nerve, from 
which each one receives a little filament, so as to 
present, according to Miiller, the following disposition. 

(Fig. 18). The cones are per- 
fectly transparent, but sepa- 
rated from each other by 
walls of pigment, in such a 
manner, that only those rays 
which are parallel to the 
axes, can reach the retina A ; 
all those which enter ob- 
liquely, are lost ; so that of 
all the rays which proceed 
from the points a and Z>, only the central ones in each 
pencil will arrive at the optic nerve (rf) ; the others will 
strike against the walls of the cones. To compensate 
for the disadvantage of such an arrangement, and for the 
want of motion, the number of fafettes is greatly multi- 
plied, so that no less than 25,000 have been counted in 
a single eye. The image on the retina, in this case, may 
be compared to a mosaic, composed of a great number of 
small images, each of them representing a portion of the 
figure. The entire picture is, of course, more perfect, 



in proportion as the pieces are smaller and more nume- 

89. Compound eyes, being destitute of the optical appara- 
tus necessary to collect the rays of light, cannot adapt 
themselves to the distance of objects ; they see, but cannot 
look. The perfection of their sight depends on the number 
of fa^ettes or cones, and the manner in which they are 
placed. Their field of vision is wide, when the eye is 
prominent ; it is very limited, on the contrary, when the eye 
is flat. Thus the dragon-flies, on account of the great 
prominency of their eyes, see equally well in all directions, 
before, behind, or laterally, whilst the water-bugs, which 
have the eyes nearly on a level with the head, can see to 
only a very short distance before them. 

90. Those animals which are destitute of eyes are 
either of a very inferior rank, such as most of the polypi, 
or .else they comprise animals which live under unu- 
sual circumstances, such as the intestinal worms. Even 
among the vertebrates, there are some which lack the fac- 
ulty of sight, as the Myxine glutinosa, which has merely a 
rudimentary eye concealed under the skin, and destitute of a 
crystalline. Others, which live in darkness, have not even 
rudimentary eyes, as for example, the fishes which live in 
the Mammoth Cave, (Amblyopsis spelceus), and which 
appear to want even the orbital cavity. The craw-fishes, 
(Astacus pellucidus}) of this same cave, are also blind ; 
having merely the pedicle for the eyes, without any 
traces of 

2. Hearing. 

91. To hear, is to perceive sounds. The faculty of per- 
ceiving sounds is seated in a peculiar apparatus, the EAR, 
which is constructed with a view to collect and augment the 
sonorous vibrations of the atmosphere, and convey them to 



the acoustic or auditory nerve, which arises from the poste- 
rior part of the brain. (Fig. 21, c). 

92. The ears never exceed two in number, and are 
placed, in all the vertebrates, at the hinder part of the head. 
In a large proportion of animals, as the dog, horse, rabbit, 
and most of the mammals, they are generally quite con- 
spicuous externally, and as they are at the same time 
quite movable, they become one of the prominent features of 

93. These external appendages, however, do not consti- 
tute the organ of hearing, properly speaking. The true 
seat of hearing is deeper, quite in the interior of the 
head. It is usually a very complicated apparatus, especially 
in the superior animals. In mammals it is composed of 
three parts, the external ear, the middle ear, and the internal 
ear, and its structure is as follows : (Fig. 19). 

Fig. 19. 

94. The external ear, which is ordinarily regarded as the 
ear, consists of the conch, (a), and the canal which leads 
from it, the external auditory passage , (b). The first is a 



gristly expansion, in the form of a horn or a funnel, the ob- 
ject of which is to collect the waves of sound ; for this rea- 
son, animals prick up their ears when they listen ; and for 
the same reason, persons who are hard of hearing, em- 
ploy an artificial trumpet, by which they may collect the 
vibrations from a much more extended surface. The exter- 
nal ear is peculiar to mammals ; and is wanting even in a 
few aquatic species of these, such as the seals and the 
Ornithorynchus. The ear of man is remarkable for being 
nearly immovable. 

95. The middle ear has received the name of the tym- 
panic cavity (k). It is separated from the auditory passage 
by a membranous partition, the tympanum or drum (c) ; 
though it still communicates with the open air by means 
of a narrow canal, called the Eustachian tube, (i) which 
opens at the back part of the mouth. In the interior of 
the chamber, are four little bones 

of singular forms, which anatomists 
have distinguished by the names 
of malleus (Fig. 20, c), incus (n), 
stapes (s), and os orbiculare (o) ; 
which are articulated together, 
as here represented, so as to form 
a continuous chain. 

96. The internal ear, which is Fig. 20. 

also denominated the labyrinth, is an irregular cavity formed 
in the most solid par^ of the temporal bone, beyond the 
chamber of the middle ear, from which it is separated by 
a bony partition, which is perforated by two small holes, 
called, from their form, the round and the oval apertures, 
the foramen rotundum, (Fig. 19, g), and the foramen 
ovale (h). The first is closed by a membrane, similar to that 
of the tympanum, while the latter is closed by the stapes, 
one of the little bones in the chamber. 


97. Three parts are to be distinguished in the labyrinth, 
namely, the vestibule, which is the part at the entrance of the 
cavity ; the semicircular canals (d), which occupy its upper 
part, in the form of three arched tubes ; and the cochlea, 
which is a narrow canal placed beneath, at the lower part of 
the vestibule, having exactly the form of a snail-shell (e). 
The entire labyrinth is filled with a watery fluid, in 
which membranous sacs or pouches float. Within these sacs, 
the auditory nerve (f) terminates. These pouches, there- 
fore, are the actual seat of hearing, and the most essential 
parts of the ear. The auditory nerve is admitted to them 
by a long passage, the internal auditory canal. 

98. By this mechanism, the vibrations of the air are first 
collected by the external ear, whence they are conveyed 
along the auditory passage, at the bottom of which is the tym- 
panum. The tympanum, by its delicate vibrations, augments 
the sound, and transmits it to the internal ear, partly by means 
of the little bones in the chamber, which are disposed in such 
a manner that the stapes exactly fits the oval aperture, 
(foramen ovale) ; and partly by means of the air which 
strikes the membrane covering the round aperture (g),and 
produces vibrations there, analogous to those of the tympa- 
num. After all these modifications, the sonorous vibrations 
at last arrive at the labyrinth and the auditory nerve, 
which transmits the impression to the brain. 

99. But the mechanism of hearing is not so complicated 
in all classes of animals, and is found to be more and more 
simplified, as we descend the series. In birds, the middle 
and interior ears are constructed on the same plans as in the 
mammals ; but the outer ear no longer exists, and the au- 
ditory passage, opening on a level with the surface of the head 
behind the eyes, is surrounded only by a circle of peculiarly 
formed feathers. The bones of the middle ear are also 
jass numerous, there being generally but one. 


100. In reptiles, the whole exterior ear disappears ; the 
auditory passage is always wanting, and the tympanum be- 
comes external. In some toads, even the middle ear also 
is completely wanting. The fluid of the vestibule is 
charged with salts of lime, which frequently give it a milky 
appearance, and which, when examined by the microscope, 
are found to be composed of an infinite number of crystals. 

101. In fishes, the middle and external ear are both 
wanting ; and the organ of hearing is reduced to a membra- 
nous vestibule, situated in the cavity of the skull, and 
surmounted by semicircular canals, from one to three in 
number. The liquid of the vestibule contains chalky con- 
cretions of irregular forms, which are called Otolites, and 
whose use is doubtless to render the vibration of sounds 
more sensible. 

102. In crabs, the organ of hearing is found on the lower 
face of the head, at the base of the large antennae. It is a 
bony chamber closed by a membrane, in the interior of 
which is suspended a membranous sac filled with water. 
On this sac, the auditory nerve is expanded. In the cuttle- 
fish, the vestibule is a simple excavation of the cartilage of 
the head, containing a little membranous sac, in which the 
auditory nerve terminates. 

103. Finally, some insects, the grasshopper for in- 
stance, have a sort of ear, no longer situated in the head, 
as with other animals, but in the legs ; and from this fact, 
we may be allowed to suppose, that if no organ of hearing 
has yet been found in most insects, it is because it 
has been sought for in the head only. 

104. It appears from these examples, that the part of the 
organ of hearing which is uniformly present in all animals 
furnished with ears, is precisely that in which the auditory 
nerve ends, that is to say, this is the essential part of the or- 
gan. The other parts of the apparatus, the tympanum, 



auditory passage, and even the semicircular canals, have for 
their object merely to cause the perception of sound with 
more precision and accuracy. Hence we may conclude 
that hearing is dull in animals where the organ is reduced 
to its most simple form ; and that animals which have 
merely a simple membranous sac, without tympanum and 
auditory passage, as the fishes, or without semi-circular 
canals, as the crabs, perceive sounds but in a very imperfect 



3. Of Smell. 

SMELL is the faculty of perceiving odors. Like 

sight and hearing, 
smell depends upon 
special nerves, the 
olfactory (a), which 
form the first pair 
of cerebral nerves, 
and which, in the 
embryo, are direct 

Fig. 21. Head of a Crow. prolongations of the 

a, olfactory nerve ; b, optic nerve ; c, auditory i 
nerve ; d, cerebrum ; e, cerebellum. 

106. The organ of smell, is the NOSE. Throughout the 
series of vertebrates, it makes a part of the face, and in 
man, by reason of its prominent form, it becomes one of the 
dominant traits of his countenance ; in other mammals, the 
nose loses this prominency by degrees, and the nostrils 
no longer open downwards, but forwards. In birds, the 
position of the nostrils is a little different ; they open farther 
back and higher, at the origin of the beak. 

107. The nostrils are usually two in number. They are 
similar openings, separated by a partition upon the middle 
line of the body. In man and the mammals, the outer walls 
of the nose are composed of cartilage ; but internally, the 


nostrils communicate with bony cavities situated in the 
bones of the face and forehead. These cavities are lined by 
a thick membrane, the pituitary membrane, on which are 
expanded the nerves of smell, namely, the olfactory nerve, 
and some filaments of the nerve which goes to the face. 

108. The process of smelling is as follows. Odors are 
particles of extreme delicacy which escape from very 
many bodies, and are diffused through the air. These par- 
ticles are recognized by the nerves of smell only, which 
transmit the impressions made by them to the brain. 
Smell differs, consequently, from sight and hearing, in being 
produced by a material body, and not by a simple undulatory 
movement. To facilitate the perception of odors, the 
nostrils are placed in the course of the respiratory passages, 
so that all the odors which are diffused in the air inspired 
pass over the pituitary membrane. 

109. The perfection of smell depends on the extent to 
which the membrane is developed. Man is not so well 
endowed in this respect as many animals, which have the 
internal surface of the nostrils extremely complicated, as 
it is especially among the beasts of prey. 

110. The sense of smell in Reptiles is less delicate than in 
the mammals ; the pituitary membrane also is less de- 
veloped. Fishes are probably still less favored in this 
respect. As they perceive odors through the medium of 
water, we should anticipate that the structure of their 
apparatus would be different from that of animals which 
breathe air. Their nostrils are mere superficial pouches, 
lined with a membrane gathered into folds which gen- 
erally radiate from a centre, but are sometimes arranged 
in parallel ridges on each side of a central band. The 
perfection of smell depending on the amount of surface 
exposed, it follows that those fishes which have these 



folds most multiplied are also those in which this sense is 
most acute. 

111. No special apparatus for smell has yet been found 
in Invertebrates. And yet there can be no doubt that in- 
sects, crabs, and some mollusks perceive odors, since they 
are attracted from a long distance by objects which diffuse 
them. Some of them may be deceived by odors similar 
to those of their prey ; which clearly shows that they are 
led by this sense. 

4. Of Taste. 

112. TASTE is the sense by which the flavor of bodies is 
perceived. It guides animals in the choice of their food, and 
warns them to abstain from what is noxious. There is 
also an intimate connection between the taste and the smell, 
so that both these senses are called into requisition in 
the selection of food. To perceive the flavor of a body, it 
must come into immediate contact with the nerves of taste, 
and hence these nerves are distributed at the entrance to 
the digestive tube, on the surface of the tongue and the 

113. The nerves of taste are not so strictly special as 
those of sight and hearing. They do not proceed from 
one single trunk, and, in the embryo, do not correspond to 
a particular part of the brain. The tongue in particular, 
receives nerves from several trunks ; and taste is perfect in 
proportion as the nerves which go to the tongue are more 
minutely distributed. The extremities of the nerves gene- 
rally terminate in little asperities of the surface, called papil- 
la. Sometimes these papillse are very harsh, as in the cat 
and the ox ; and again they are very delicate, as in the 
human tongue, in that of the dog, horse, &c. 

114. Birds have the tongue cartilaginous, sometimes 
beset with little stiff points ; sometimes fibrous and fringed 


at the edges. In the parrots, it is thick and fleshy ; 
or it is even barbed at its point as in the woodpeckers. 
In some reptiles, the crocodile, for example, the tongue 
is adherent ; in others, on the contrary, it is capable of 
extensive motion, and serves as an organ of touch, as in the 
serpents, or it may be thrust out to take prey, like that of 
the chameleon. In fishes it is usually cartilaginous as in 
birds, generally adherent, and its surface is frequently cov- 
ered with teeth. Some of the inferior animals select their 
food with no little discernment. Thus, flies always select 
the sugary portions of bodies. Some of the mollusks, as the 
snails for example, are particularly dainty in the choice of 
their food. 

115. It is to be presumed that in animals which have a 
cartilaginous tongue the taste must be very obtuse, espe- 
cially in those which, like most fishes and many granivorous 
birds, swallow their prey without mastication. In fishes, 
especially, the taste is very imperfect, as is proved by their 
readily swallowing artificial bait. It is probable that they 
are guided in the choice of their prey by sight, rather 
than by taste or smell. 

116. In general, the taste is but imperfectly developed 
except in the mammals, and they are the only animals 
which enjoy the flavor of their food. With man, the culti- 
vation of this sense becomes a matter of study ; and it is 
capable of being brought to a high degree of delicacy. 

5. Of Touch. 

117. The sense of TOUCH is merely a peculiar manifesta- 
tion of the general sensibility, seated in the skin, and 
dependent upon the nerves of sensation which expand over 
the surface of the body. By the aid of this general sensi- 
bility, we learn whether a body is hot or cold, wet or dry. 
We may also, by simple contact, gain an idea, to a certain 


extent, of the form and consistence of a body, as for exam- 
ple, whether it be sharp or blunt, soft or hard. 

118. This faculty resides more especially in the hand, 
which is not only endowed with a more delicate tact, but 
owing to the disposition of the fingers and the opposition of 
the thumb to the other fingers, is capable of so moulding 
itself around objects, as to multiply the points of contact. 
Hence touch is an attribute of man rather than of other 
animals ; for among these latter, scarcely any, except the 
monkeys, have the faculty of touch in their hands, or as it 
is technically termed, of palpation. 

119. In some animals, this faculty is exercised by other 
organs. Thus the trunk of the elephant is a most perfect 
organ of touch ; and probably the mastodon, whose nume- 
rous relics are found scattered in the superficial layers of 
the earth's crust, was furnished with a similar organ. 
Serpents make use of their tongue for touch ; insects 
employ their palpi, and snails their tentacles for the same 

6. The Voice. 

120. Animals have not only the power of perceiving, 
but many of them have also the faculty of producing 
sounds of every variety, from the roaring of the lion to the 
song of the bird as it salutes the rising sun. It is moreover 
to be remarked that those which are endowed with a voice, 
are precisely those in whom the organ of hearing is most 

121. Animals employ their voice, either for communica- 
tion with each other, or to express their sensations, their en- 
joyments, their sufferings. Nevertheless, this faculty is en- 
joyed by but a small minority of animals ; with but very 
few exceptions, only the mammals, the birds, and a few 
reptiles are endowed with it. All others are dumb. 


Worms and insects have no true voice ; for we must not 
mistake for it, the buzzing of the bee, which is merely 
a noise created by the vibration of the wings ; nor the 
shrill sound of the cricket, which is caused by the friction 
of his legs against the wing ; nor the shriek of the locust, 
produced by the resonance of his cymbals, when put in vi- 
bration by the opening and closing of the wings. 

122. Consequently, were the mammals, the birds and the 
frogs, to be struck out of existence, the whole Animal King- 
dom would be dumb. It is difficult for us, living in the 
midst of the thousand various sounds which strike our ear 
from all sides, to conceive of such a state. Yet, such a state 
did prevail for thousands of ages, on the surface of our globe, 
when the watery world alone was inhabited, and before man, 
the birds, and the mammals were called into being. 

123. In man and the mammals, the voice is formed in an 
organ called the larynx, situated at the upper part of the 
windpipe, below the bone of the tongue (a). 

The human larynx, the part called Adam's NJ // 

apple, is composed of several cartilaginous 
pieces, called the thyroid cartilage (&), the b- 
cricoid cartilage (c), and the small aryte- 
noid cartilages. Within these, are found two 
large folds of elastic substance, known by the 
name of the vocal cords (w). Two other Fig. 22. 
analogous folds, the superior ligaments of the glottis (ri), 
are situated a little above the preceding. The glottis (o), 
is the space between these four folds. The arrangement of 
the vocal cords, and of the interior of the glottis in man, is 
indicated by dotted lines in Fig. 22. 

124. The mechanism of the voice is as follows : the air, 
on its way to the lungs, passes the vocal cords. So long as 
these are in repose, no sound is produced ; but the moment 
they are put upon the stretch, they oppose an obstacle to the 
current of air, and it cannot pass without causing them to 




vibrate. These vibrations produce the voice ; and as the 
vocal cords are susceptible of different degrees of tension, 
these tensions determine different sounds ; giving an acute 
tone when the tension is great, but a grave and dull one 
when the tension is feeble. 

125. Some mammals have, in addition, large cavities 
which communicate with the glottis, and into which the air 
reverberates, as it passes the larynx. This arrangement is 
especially remarkable in the howling monkeys, which are dis- 
tinguished above all other animals, for their deafening howls. 

126. In birds, the proper larynx is very simple, destitute 
of vocal cords, and incapable of producing sounds ; but at 
the lower end of the windpipe there is a second or inferior 
larynx, which is very complicated in structure. It is a kind 

of bony drum (a), having with- 
in it two glottides, formed at 
the top of the two branches (Z>&) 
of the windpipe (c), each 
provided with two vocal cords. 
The different pieces of this ap- 
Iparatus are moved by peculiar 
muscles, the number of which 
varies in different families. In 
birds which have a very mono- 
|^l tonous cry, such as the gulls, 
the herons, the cuckoos, and 

the mergansers (Fig. 23), there is but one or two pairs; 

parrots have three ; and the birds of song have five. 

127. Man alone, of all the animal creation, has the power 
of giving, to the tones he utters, a variety of definite sounds ; 
in other words, he alone has the gift of speech. 

Fig. 23. 



128. BESIDES the material substance of which the body is 
constructed, there is also an immaterial principle, which, 
though it eludes detection, is none the less real, and to 
which we are constantly obliged to recur in considering the 
phenomena of life. It originates with the body, and is de- 
veloped with it, while yet it is totally apart from it. The 
study of this inscrutable principle belongs to one of the 
highest branches of Philosophy ; and we shall here merely 
allude to some of its phenomena which elucidate the de- 
velopment and rank of animals. 

129. The constancy of species is a phenomenon depend- 
ing on the immaterial nature. Animals, and plants also, pro- 
duce their kind, generation after generation. We shall 
hereafter show that all animals may be traced back, in the 
embryo, to a mere point upon the yolk of the egg, bearing 
no resemblance whatever to the future animal. But even 
here, an immaterial principle, which no external influence 
can prevent or modify, is present, and determines its fu- 
ture form ; so that the egg of the hen can produce nothing 
but a chicken, and the egg of the cod-fish produces only the 
cod. It may therefore be said with truth, that the chicken 
and the cod existed in the egg before their formation. 

130. PERCEPTION is a faculty springing from this princi- 


pie. The organs of sense are the instruments for perceiving 
sensations, but they are not the faculty itself, and indeed 
without it they would be useless. We all know that the eye 
and ear may be open to the sights and sounds about us, but 
if the mind happens to be preoccupied, we perceive them 
not. We may even be searching for something which actu- 
ally lies within the compass of our vision ; the light enters 
the eye as usual, and the image is formed on the retina ; 
but, to use a common expression, we look without seeing, 
unless the mind that perceives is directed to the object. 

131. In addition to the faculty of perceiving sensations, 
the higher animals have also the faculty of recalling 
past impressions, or the power of memory. Many animals 
retain a recollection of pleasure or pain that they have 
experienced, and seek or avoid the objects which these sen- 
sations may have produced ; and in doing so, they give 
proof of judgment. 

132. Finally, we notice in some animals acts which 
prove that they have the faculty of comparing their sensations 
and their judgments ; in other words, that they carry on a 
process of reasoning. 

133. These different faculties, taken together, constitute 
intelligence. In man, this superior principle, which is an 
emanation of the divine nature, manifests itself in all its 
splendor. God " breathed into him the breath of life, and 
man became a living soul." It is his prerogative, and his 
alone, to be enabled to guide his conduct by the deductions 
of reason ; he has not only the faculty of exercising his 
judgment upon the objects which surround him, and of ap- 
prehending the many relations which exist between himself 
and the external world ; he may also apply his reason to 
immaterial things, observe the operations of his own intel- 
lect, and, by the analysis of his faculties, may arrive at the 
consciousness of his own nature, and even conceive of 
that Infinite Spirit, " whom none by searching can find out." 


134. Other animals cannot aspire to conceptions of this 
kind ; they contemplate merely those objects which imme- 
diately strike the senses, and without exercising any con- 
tinuous effort of the reasoning faculty in regard to them. 
Their conduct, moreover, is regulated by another princi- 
ciple of inferior order, still derived from the immaterial 
principle, called INSTINCT. 

135. Under the guidance of Instinct, animals are enabled 
to perform certain operations, without instruction, in one un- 
deviating manner. When man chooses wood and stone, as 
the materials for his dwelling, in preference to straw and 
leaves, it is because he has learned by experience, or because 
his associates have informed him, that these materials are 
more suitable for the purpose. But the bee requires no in- 
structions in building her comb. She selects, without hesita- 
tion, the fittest materials ; and the young bee exhibits, in this 
respect, as much discernment as those who have had the 
benefit of long experience. She performs her task without 
previous study, and, according to all appearances, without 
the consciousness of its utility, being in some sense impelled 
to it by a blind impulse. 

136. If, however, we judge of the instinctive acts of ani- 
mals compared with the acts of intelligence, by the relative 
perfection of their products, we may be led into gross errors, 
as a single example will show. No one will deny that the 
honey-comb is constructed with more art and care than the 
huts of many tribes of men. And yet, who would presume 
to conclude from this, that the bee is superior in intelligence 
to the inhabitant of the desert or of the primitive forest ? 
It is evident, on the contrary, that in this particular case, we 
are not to judge of the artisan by his work. As a work of 
man, a structure as perfect in all respects as the honey- 
comb would indicate very complicated mental operations, 
and probably numerous preliminary experiments. 


137. The instinctive actions of animals relate either to 
the procuring of food, or to the rearing of their young ; 
in other words, they have for their end the preservation of 
the individual and of the species. It is by instinct that the 
leopard conceals himself, and awaits the approach of his 
prey. It is equally by instinct that the spider spreads his 
web to entangle the flies which approach it. 

138. Some animals go beyond these immediate precau- 
tions ; their instinct leads them to make provision for the 
future. Thus the squirrel lays in his store of nuts and 
acorns during autumn, and deposits them in cavities of 
trees, which he readily finds again in winter. The hamster 
digs, by the side of his burrow, compartments for magazines, 
which he arranges with much art. Finally, the bee, 
more than any other animal, labors in view of the future ; 
and for this reason, she has become the emblem of order 
and domestic economy. 

139. Instinct exhibits itself, in a no less striking manner, 
in the anxiety which animals manifest for the welfare of 
their anticipated progeny. All birds build nests for the 
shelter and nurture of their young, and in some cases, these 
nests are made exceedingly comfortable. Others show 
very great ingenuity in concealing their nests from the eyes 
of their enemies, or in placing them beyond their reach. 
There is a small bird in the East Indies, the tailor bird, 
(Sylvia sutoria), which spins wool or cotton into threads, 
with its feet and beak, and uses it to sow together the 
leaves of trees for its nest. 

140. The nest of the fiery hang-bird, (Icterus Baltimore), 
dangling from the extremity of some slender, inaccessible 
twig, is familiar to all. The beautiful nest of the humming- 
bird, seated on a mossy bough, and itself coated with lichen 
and lined with the softest down from the cotton-grass or the 
mullein leaf, is calculated equally for comfort and for es- 
caping observation. An East Indian bird, (Ploceus Philippi- 


nus,) not only exhibits wonderful devices in the construction, 
security, and comfort of its nest, but displays a still further 
advance towards intelligence. The nest is built at the tips 
of long pendulous twigs, usually hanging over the water. It 
is composed of grass, in such a manner as to form a com- 
plete thatch. The entrance 
is through a long tube run- 
ning downwards from the 
edge of the nest ; and the 
lower end of it is so imper- 
fectly woven, that any ser- 
pent or squirrel, in attempting 
to enter the aperture, would 
detach the fibres, and fall to 
the ground. But the male, 
who has no occasion for a 
nest, builds his thatched dome, 
similar to that of the female, Fig. 24. 

and by its side ; but makes simply a perch across the bottom 
of the dome, without the nest-pouch or tube. 

141. But it is among insects, that this instinctive solici- 
tude for the welfare of the progeny is everywhere exhibited 
in the most striking manner. The bees and wasps not only 
prepare cells for each of their eggs, but take care, before 
closing the cells, to deposite in each of them something ap- 
propriate for the nourishment of the future young. 

142. It is by the dictate of instinct also, that vast numbers 
of animals of the same species associate, at certain periods 
of the year, for migration from one region to another ; as 
the swallows and passenger pigeons, which are sometimes 
met with in countless flocks. 

143. Other animals live naturally in large societies, and 
labor in common. This is the case with the ants and bees. 
Among the latter, even the kind of labor for each member 
of the community is determined beforehand, by instinct. 


Some of them collect only honey and wax ; while others 
are charged with the care and education of the young ; and 
still others, are the natural chiefs of the colony. 

144. Finally, there are certain animals so guided by their 
instinct as to live like pirates, on the avails of others' 
labor. The Lestris or Jager will not take the trouble to 
catch fish for itself, but pursues the gulls, until, worn out 
by the pursuit, they eject their prey from their crop. Some 
ants make war upon others less powerful, take their young 
away to their nests, and oblige them to labor in slavery. 

145. There is a striking relation between the volume of 
the brain, and the degree of intelligence which an animal 
may attain. The brain of man is the most voluminous 
of all, and among other animals there is every grada- 
tion in this respect. In general, an animal is the more 
intelligent, in proportion as its brain bears a greater re- 
semblance to that of man. 

146. The connection between instinct and the nervous 
system does not present so intimate a correspondence as 
exists between the intellect and the brain. Animals which 
have a most striking development of instinct, as the ants and 
bees, belong to a division of the Animal Kingdom where the 
nervous system is much less developed than that of the ver- 
tebrates, since they have only ganglions, without a proper 
brain. There is even a certain antagonism between instinct 
and intelligence, so that instinct loses its force and peculiar 
character, whenever intelligence becomes developed. 

147. In man, instinct plays but a secondary part, but he 
is not entirely devoid of it. Some of his actions are entirely 
prompted by instinct, as for instance, the attempts of the in- 
fant to nurse. This fact again, that instinctive actions pre- 
ponderate in infancy, when intelligence is but slightly de- 
veloped, goes to confirm the two last propositions. 




148. THE power of voluntary motion is the second grand 
characteristic of animals (57). Though they may not all 
have the means of transporting themselves from place to 
place, there is no one which has not the power of executing 
some motions. The oyster, although fixed to the ground, 
opens and closes its shell at pleasure ; and the little coral 
animal protrudes itself from its retreat, and retires again at 
its will. 

149. The movements of animals are effected by means 
of muscles, which are organs designed expressly for this 
purpose, and which make up a large portion of the body, 
that part which is commonly called flesli. They are com- 
posed of a series of fleshy bundles, which are readily seen 
in boiled meat. These bundles are again composed of par- 
cels of still more delicate fibres, called muscular fibres (45), 
and in which alone the property of elongation and contrac- 
tion resides. 

150. The motions of animals and plants depend, there- 
fore, upon causes essentially different. The expansion and 




closing of the leaves and blossoms of plants, which are their 
most obvious motions, are due to the influence of light, heat, 
moisture, cold, and similar external agents ; but all the mo- 
tions peculiar to animals are produced by a cause residing 
within themselves, namely, the contractility of muscular 


151. The cause which determines contractility resides in 
the nerves, although its action is not precisely known. 

We only know that 
each muscular bun- 
dle receives one or 
more nerves, whose 
filaments pass across 

in the figure. It has 
also been shown, by 

Fig. 25. experiment, that when 

a nerve going from the brain to a muscle is severed, the 
muscle instantly loses its power of contracting, or, in other 
words, is paralyzed. 

152. The muscles may be classified, according as they 
are more or less under the control of the will. The con- 
tractions of some of them are entirely dependent on the 
will, as the muscles of the limbs which are used for locomo- 
tion. Others are quite independent of it, like the con- 
tractions of the heart and stomach. The muscles of res- 
piration act independently of the will, but are partially sub- 
ject to it ; thus, when we attempt to hold the breath, we 
arrest, for the moment, the action of the diaphragm. 

153. In the great majority of animals, motion is greatly 
aided by the presence of solid parts, of a bony or horny 
structure, which either serve as firm attachments to the 
muscles, or, being arranged so as to act as levers, they 


increase the force and precision of the movements. The 
solid parts are usually so arranged as to form for the body 
a substantial frame work, which has been variously desig- 
nated in the several classes of animals, as the test, shell, 
carapace, skeleton, fyc. The study of these solid parts con- 
stitutes the most important branch of comparative anatomy. 
Their characters are the most constant and enduring of all 
others. Indeed, these solid parts are all that remains to us of 
the numerous extinct races of animals of past geological 
eras ; and from these alone, we are to determine the struc- 
ture and character of the ancient fauna. 

154. Most of the Radiata have a calcareous test or crusty 
shell. In the Polypi, this structure, when it exists, is usually 
very solid, sometimes in the form of a simple internal 
stem, or extensively branched, as in the sea-fans ; and 
sometimes in solid masses, furnished at the sides with nu- 
merous cavities, in which the animals are lodged, with the 
power, however, of protruding and retracting themselves at 
pleasure, by means of their muscles, as in the corals. In 
the Echinoderms, the test is brittle, and intimately united 
with the soft parts. It is composed 

of numerous little plates, some- 
times consolidated and immovable, 
as in the sea-urchins, (Fig. 26), 
and sometimes so combined, as to 
allow of various motions, as in the Fig. 26. 

star- fishes, (Fig. 17), which use their arms both for crawl- 
ing and swimming. 

155. In the Mollusks, the solid parts are secreted by the 
skin, most frequently in the form of a calcareous shell of 
one, two, or many pieces, serving for the protection of the 
soft parts which they cover. These shells are generally so 
constructed as to allow the animal to retire and conceal 
itself completely within their cavities. In a few, the shell 


is too small for this purpose, and in some it exists only at 
a very early period, and is lost as the animal is de- 
veloped, so that at last there is no other covering than a 
slimy skin. In others, the skin becomes so thick and firm 
as to have the consistence of elastic leather ; or it is gelati- 
nous or transparent, and what is very curious, the tissues 
are the same as those of woody fibre, as for example, in the 
Ascidia. As a general thing, these solid parts do not aid in 
locomotion, so that the mollusksare mostly sluggish animals. 
It is only in a few rare cases that the shell becomes a true 
lever, as in the Scollops, (Pecten) which use their shells as 
oars, in swimming. 

156. The muscles of mollusks either form a flat disc, 
or are distributed in the skin so as to dilate and contract it, 
or are arranged about the mouth and tentacles, which they 
put in motion. However varied the disposition of the muscles 
may be, they always form very considerable masses, in pro- 
portion to the size of the animal, and have a soft and mu- 
cous appearance, such as is not seen in the contractile fibres 
of the other departments of the Animal Kingdom. This pe- 
culiar aspect no doubt arises from the numerous small 
cavities found in the muscles, and the mucous glands which 
are distributed through them. 

157. In the Articulated animals, the solid parts are rings, 
generally of a horny structure, but sometimes calcareous, 
and successively fitting into each other. The tail of a 
lobster gives a good idea of this structure, which differs, in 
the several classes of this department, merely as to volume, 
form, solidity, number of pieces, and the degree of motion 
which one ring has upon another. In some groups the 
rings are consolidated, so as to form a shield or carapace, 
such as we see in the crabs. In others, the rings are so 
soft that the body is capable of changing into every possi- 
ble form, as in the leeches and worms generally. 



158. A variety of appendages are attached to these 
rings, such as jointed legs, or in place of them, stiff bristles, 
oars fringed with silken threads, wings either firm or mem- 
branous, tentacles or antenna?, movable arms which per- 
form the office of jaws, &c. But, however diversified this 
solid apparatus may be, it is universally the case that the 
rings, to which every part may be referred as to a type, 
constitute but a single simple cavity, in which all the organs 
are enclosed, the nervous system as well as the organs 
of vegetative life (63). 

159. The muscles which move 
all these parts have this peculiar- 
ity, that they are all situated within 
the solid parts, and not on their ex- 
ternal face, as in the vertebrates ; 
and also that the muscular bundles, 
which are very considerable in 
number, have the form of ribbons, 
or fleshy strips, with parallel 
fibres of remarkable whiteness. 

Figure 27 represents the disposi- Fig. 27. 

tion of the muscles of the caterpillar which destroys the 
willow, (Cossus ligniperdd). The right side represents 
the superficial layer of muscles, and the left side the deep- 
seated layer. 

160. The Vertebrata, like the articulated animals, have 
solid parts at the surface, as the hairs and spines of mam- 
mals, the feathers and claws of birds, the bucklers and 
scales of reptiles and fishes, &c. But they have besides 
this, throughout the interior of the whole body, a solid 
framework not found in the other departments, well known 
as the SKELETON. 

161. The skeleton is composed of a series of separate 




bones, called vertebrse, united to each other by ligaments. 
Each vertebra has a solid centre with four branches, two of 
A, which ascend and form an arch above, and 

two descend, forming an arch below the 
body of the vertebra. The upper arches 
form a cavity (a) which, along the region 
of the trunk, encloses the spinal marrow, 
and in the head receives the brain (61). 
The lower arches (Z>) form a cavity, simi- 
lar to the superior one, for containing the 
organs of nutrition, and reproduction ; 
they sometimes meet below, but generally 
they remain separated, so that the inferior 
cavity of the body is enclosed, in part, by 
fleshy walls. Every part of the skeleton 
may be reduced to this fundamental type, 
the vertebra, as will be shown, when treating especially of 
the vertebrate animals ; so that between the pieces of 
the head, the trunk, or the tail, we have only differences 
in the degree of development of the body of the ver- 
tebra, or of its branches, and not different plans of organ- 

162. The muscles which move this solid frame -work of 
the vertebrata are disposed around the vertebrae, as is 

Fig. 28. 

Fig. 29. 

well exemplified among the fishes, where there is a band 
of muscles for each vertebra. In proportion as limbs 



are developed, this intimate relation between the mus- 
cles and the vertebra 
goes on diminishing. The 
muscles are more con- 
centrated about the limbs, 
where the greatest amount 
of muscular force is re- 
quired. For this reason, 
the largest masses of flesh, 
in the highest vertebrates 
are found about the shoul- 
ders and hips ; while in 
the fishes, they are con- 
centrated about the tail, Fig. so. 
which is the part on which they principally depend for 



163. One of the most curious and important applications 
of this apparatus of bones and muscles, is that for LOCOMO- 
TION. By this is understood the movement by which an 
animal passes from place to place, in the pursuit of pleasure, 
sustenance or safety, in distinction from those motions 
which are performed equally well while stationary, such 
as the acts of respiration, mastication, &c. 

164. The means which nature has brought into action to 
effect locomotion under all the various circumstances in 
which animals are placed, are very diversified ; and the 
study of their adaptation to the necessities of animals is one 
of the highest interest in a mechanical, as well as in a 
zoological point of view. Two general plans may be noticed, 


under which these varieties may be arranged. Either the 
whole body is concerned in effecting locomotion, or only 
some of its parts are employed for the purpose. 

165. The jelly-fishes (Medusaa) 
swim by contracting their umbrella- 
shaped bodies upon the water con- 
tained within, and its resistance 
urges them forwards. Many others 
are provided with a sac or siphon, 
which they fill with water. By fore- 
Fig. 31. ing out the water suddenly, a jet is 
produced, which is resisted by the surrounding water, and 
the animal is thus propelled. The Biche-le-mar, (Holo- 
thuria), the cuttle-fishes, the Salpas, &c., employ this method. 

166. Others contract small portions of the body in suc- 
cession, which being thereby rendered firmer, serve as 
points of resistance, against which the animal may strive, 
in urging the body onwards. The earth-worm, whose body 
is composed of a series of rings united by muscles, and 
shutting more or less into each other, has only to close up 
the rings at one or more points, to form a sort of fulcrum, 
against which the rest of the body exerts itself in extend- 
ing forwards. 


167. Some have, at the extremities of the body, a cup or 
some other organ for maintaining a firm hold, each one 
acting in turn as a fixed point. Thus the Leech has a cup 
or sucker at its tail, by which it fixes itself ; the body is 
then elongated by the contrac- 
tion of the muscular fibres! 

which encircle the animal ; the 

other end is fixed by a similar | 

sucker, then by the contraction Fig. 32. 

of muscles running lengthwise, the body is shortened, and 

the tail is brought forwards to perform the same process 


again. Most of the bivalve mollusks, such as the clams, 
move from place to place, in a similar way. A fleshy 
organ, called the foot, is thrust forward, and its extremity 
fixed in the mud or to some firm object, when it contracts, 
and thus draws along the body, and the shell enclosing it. 
The snails and many similar animals have the under surface 
of the body composed of an infinitude of very short muscles 
which, by successive contractions, so minute indeed as 
scarcely to be detected, enable them to glide along smoothly 
and silently, without any apparent muscular effort. 

168. In the majority of animals, however, locomotion is 
effected by means of organs specially designed for the pur- 
pose. The most simple organs are the minute hair-like 
cilicR, which cover the body of most of the microscopic 
infusory animalcules, and which, by their incessant vibrations, 
cause rapid movements. The sea-urchins and star-fishes 
have little thread-like tubes issuing from eveiy side of the 
body, furnished with a sucker at the end. By attaching 
these to some fixed object, they are enabled to draw or roll 
themselves along ; but their progress is always slow. In- 
sects are distinguished for the great perfection of their or- 
gans of motion. They have at least three pairs of legs, and 
usually wings also. The Crustacea generally have at least 
five pairs of legs, which are used for both swimming and 
walking. The Worms are much less active ; some of them 
have only short bristles at 

their sides for locomotion ; 
and even those that have 
numerous feet, like the cen- 
tipedes, are not distin- 
guished for agility. Some Fig. 33. 
of the marine species use their gills for paddles. (Fig. 33). 

169. Among the Vertebrata, we find the greatest variety 
of the organs and modes of locomotion, as well as the great- 


est perfection, whatever may be the element in which they 
are exercised. The sailing of the eagle, the bounding of 
the antilope, the swimming of the shark, are not equalled 
by any movements of insects. This superiority is due to 
the internal skeleton, which, while it admits a great display 
of force, gives to the motions, at the same time, a great 
degree of precision. 

1. Plan of the Organs of Locomotion. 

170. The organs of progression in vertebrated animals 
never exceed four in number, and to them the term limits is 
more particularly applied. The study of these organs, as 
characteristic of the different groups of vertebrate animals, is 
most interesting, especially when prosecuted with a view to 
trace them all back to one fundamental plan, and to ob- 
serve the modifications, oftentimes very slight, by which 
a very simple organ is adapted to every variety of move- 
ment. No part of the animal structure more fully illustrates 
the unity of design or the skill of the Intellect which has 
so adapted a single organ to such multiplied ends. On this 
account, we propose to illustrate this subject somewhat in 

171. It is easy to see that the wing which is to sustain 
the bird in the air, must be different from the leg of the stag 
which is made for running, or the fins of the fish that swims. 
But, notwithstanding this diversity, the wing of the bird, the 
leg of the stag, and the anterior fin of the fish, may 
still be traced to the same plan of structure ; and if we 
examine their skeletons, we find the same fundamental 
parts. In order to show this, it is necessary to give a short 
description of the composition of the arm or anterior ex- 

172. The anterior member, in the vertebrates, is invaria- 
bly composed of the following bones ; 1. The shoulder- 





\ I 



Hade or scapula (a), a broad and flat bone, applied upon 
the bones of the trunk ; 2. The arm (Z>), formed of a single 
long cylindrical bone, the humerus ; 3. The fore arm, com- 
posed of two long bones, the radius (c), and ulna (d), 
which are often fused into one ; 4. The hand, which is 
composed of a series of bones, more f .o 

or less numerous in different classes, 
and which is divided into three parts, 
namely, the carpus or wrist (e), the 
metacarpus or palm (f), and the 
fingers (g). The clavicle or collar- 
lone (o), when it exists, belongs also 
to the anterior member. It is a 
bone of a cylindrical form, fixed as 
a brace between the breast-bone and 
shoulder-blade. Its use is to keep the 
shoulders separated ; to this end, we 
find it fully developed in all ani- 
mals which raise the limbs from the 
sides, as the birds and the bats. 
On the other hand, it is rudimentary, 
or entirely wanting in animals which 
move them backwards and forwards 
only, as with most quadrupeds. 

173. The following outlines will give an idea of the 
modifications which these bones present, in different 
classes. In the arm of man, (Fig. 34), the shoulder 
blade is flat and triangular ; the bone of the arm is cylindri- 
cal, and enlarged at its extremities ; the bones of the fore 
arm are about the same length as the humerus, but more 
slender ; the hand is composed of the following pieces, 
namely, eight small bones of the carpus, arranged in two 
ranks, five metacarpal bones, which are elongated, and 

Fig. 34. 



succeed those of the wrist ; five fingers of unequal length, 
one of which, the thumb, is opposed to the four others. 

174. In the stag, (Fig. 35), the bones of the fore-arm 
greatly prevail in length over that of the arm, and the radius 
no longer turns upon the ulna, but is blended with it ; but it 
is especially the metacarpal or cannon-bone, which is greatly 
developed ; and being quite as long as the fore-arm, it is 
apt to be mistaken for it. The fingers are reduced to two, 
each of which is surrounded by a hoof, at its extremity. 

175. In the arm of the lion, (Fig. 36), the arm bone is 

Fig. 36. 

stouter, the carpal bones are less numerous, and the fingers 
are short, and armed with strong, retractile claws. In the 
whale, (Fig. 37), the bones of the arm and fore arm are 
much shortened and very massive ; the hand is broad, the 
fingers strong, and distant from each other. 

Fig. 38. 

Fig. 39. 

In the bat, (Fig. 38), the fingers, with the exception of the 
thumb, which is represented by a small hook, are elongated 
in a disproportionate manner, and across them the skin is 



stretched, so as to serve the purpose of a wing. In birds, 
the pigeon, for example, (Fig. 39), there are but two fin- 
gers, which are consolidated and destitute of nails ; and the 
thumb is rudimentary. 

176. The arm of the turtle (Fig. 40) is peculiar in hav- 



Fisr. 41. 

Fig. 42. 

ing, besides the shoulder-blade, two clavicles ; the arm-bone 
is twisted outwards, as well as the bones of the fore-arm, so 
that the elbow, instead of being behind, is turned forwards; 
the fingers are long and widely separated. In the Sloth 
(Fig. 41), the bones of the arm and fore-arm are very 
greatly elongated, and at the same time very slender ; the 
hand is likewise very long, and the fingers are terminated 
by enormous non-retractile nails. The arm of the mole, 
(Fig. 42), is still more extraordinary. The shoulder-blade, 
which is usually a broad and flat bone, becomes very 
narrow ; the arm-bone, on the contrary, is contracted so 
much as to seem nearly square ; and the hand is exces- 
sively large and stout. 

177. In fishes, the form and arrangement of the bones is 
so peculiar that it is often difficult to trace their analogy to 
all the parts found in other animals ; nevertheless, the 
bones of the fore-arm are readily recognized. In the 




Cod, (Fig. 43), there are two flat and broad bones, one 
of which, the ulna (rf), presents a long point, anteriorly. 

Fig. 43. 

The bones of the carpus are represented by four nearly 
square little bones. But in these again, there are considera- 
ble variations in different fishes, and in some genera they 
are much more irregular in form. The fingers are but im- 
perfectly represented by the rays of the fin (g), which are 
composed of an infinitude of minute bones, articulated with 
each other. As to the humerus and shoulder, their analo- 
gies are variously interpreted by different anatomists. 

178. The form of the members is so admirably adapted 
to the special offices which they are designed to perform, 
that by a simple inspection of the bones of the arm, as re- 
presented in the preceding sketches, one might infer the uses 
to which they were to be put. The arm of man, with its 
radius turning upon its ulna, the delicate and pliable fingers, 
and the thumb opposed to them, bespeak an organ for the 
purpose of handling. The slender and long arm of the 
sloth, with his monstrous claws, would be extremely incon- 
venient for walking on the ground, but appropriate for seizing 
upon the branches of the trees, on which these animals 
live. The short fingers, armed with retractile nails, indicate 
the lion, at first glance, to be a carnivorous animal. The 
arm of the stag, with his very long cannon-bone, and that of 
the horse also, with its single solitary finger enveloped in a 
hoof, are organs especially adapted for running. The very 
slender, and greatly elongated fingers of the bat are ad- 
mirably contrived for the spread of a wing, without in- 


creasing the weight of the body. The more firm and solid 
arm of the hird indicates a more sustained flight. The 
short arm of the whale, with his spreading fingers, resem- 
bles a strong oar. The enormous hand of the mole, with 
its long elbow, is made for the difficult and long-continued 
efforts requisite in burrowing. The twisted arm of the tor- 
toise can be applied to no other purpose than creeping. 
And finally, the arm of the fish, completely enveloped in 
the mass of the flesh, presents, externally, a mere delicate 
balancer, the pectoral fin. 

179. The posterior members are closely analogous in 
structure to the anterior. The bones of which they are 
composed, are, 1. The pelvis, (Fig. 46), which corresponds 
to the shoulder blade ; 2. The thigh bone or femur, which is 
a simple bone like the humerus ; 3. The bones of the leg, the 
tibia andjibula, which, like the radius and ulna, sometimes 
coalesce into one bone ; and lastly, the bones of the foot, 
which are divided, like those of the hand, into three parts, 
the tarsus, metatarsus, and toes. The modifications are 
generally less marked than in the arm, inasmuch as there is 
less diversity of function ; for in all animals, without excep- 
tion, the posterior extremities are used exclusively for walk- 
ing or swimming. 

180. The anterior extremity of the vertebrates, however 

varied in form, whether it be an 
arm, a wing, or a fin, is thus 
shown to be composed of essen- 
tially the same parts, and con- 
structed upon the same general 
plan. This affinity does not extend 
to the invertebrates, although in 
Fig. 44. Fig. 45. many instances their limbs bear 

certain resemblance to those of the vertebrates, and are 
even used for similar purposes, yet they have no real 


affinity. Thus the leg of an insect (Fig. 44), and that 
of a lizard (Fig. 45) ; the wing of a butterfly and the 
wing of a bat are quite similar in form, position and 
use ; but in the bat and the lizard, the organ has an internal 
bony support, which is a part of the skeleton ; while the 
leg of the insect has merely a horny covering, proceeding 
from one of the rings of the body, and the wing of the 
butterfly is merely a fold of the skin ; showing that the limbs 
of the Articulata are constructed upon a different plan 
(157). It is by ascertaining and regarding these real affini- 
ties, that the true natural grouping of animals is to be 

2. Of Standing, and the Modes of Progression. 

181. STANDING, or the natural attitude of an animal, depends 
on the form and functions of the limbs. Most of the ter- 
restrial mammals and the reptiles, both of which employ all 
four limbs in walking, have the back-bone horizontal, and 
resting at the same time upon both the anterior and posterior 
extremities. Birds, whose anterior limbs are intended for a 
purpose very different from the posterior, stand upon the 
latter, when at rest, although the back-bone is still very 
nearly horizontal. Man alone, is designed to stand upright, 
with his head supported on the summit of the vertebral col- 
umn. Some monkeys can rise upon the hind-legs into the 
erect posture ; but it is evidently a constrained posture, and 
not their habitual attitude. 

182. That an animal may stand, it is requisite that the 
limbs should be so disposed that the centre of gravity, in 
other words, the point about which the body balances itself, 
should fall within the space included by the feet. If the 
centre of gravity is outside of these limits, the animal 
falls to the side to which the centre of gravity inclines. On 


this account, the albatross, and some other aquatic birds 
which have the feet placed very far back, cannot use 
them for walking. 

183. The more numerous and the more widely separated 
are the points of support, the firmer an animal stands. On 
this account, quadrupeds are less liable to lose their balance 
than birds. If an animal has four legs it is not necessary 
that they should have a broad base. Thus we see that most 
quadrupeds have slender legs touching the earth by only a 
small surface. Broad feet would only increase the weight 
of the limbs, without adding to their stability. Birds are 
furnished with long toes, which, as they spread out, subserve 
the purpose of tripods. Moreover, the muscles of the toes are 
so disposed that the weight of the bird causes them to con- 
tract firmly, so that it can sleep standing upon the roost 
without effort, in perfect security. 

Fig. 46. 

184. In quadrupeds, the joints at the junction of the limbs 
with the body bend readily in one direction only, that is, to- 
wards the centre of gravity ; so that if one limb yields, the 
tendency to fall is counteracted by the resistance of the limbs 
at the other extreme of the body. The same antagonism 
is observed in the joints of the separate limbs, which are 
flexed alternately in opposite directions. Thus the thigh 
bends forwards, and the leg backwards ; while the arm 
bends backwards, and the fore-arm forwards. Different 


terms have been employed to express the various modes of 
progression, according to the rapidity or the succession in 
which the limbs are advanced. 

185. PROGRESSION is a forward movement of the body, 
effected by successively bending and extending the limbs. 
WALKING is the ordinary and natural gait, and other 
paces are only occasionally employed. When walking 
is accomplished by two limbs only, as in man, the body 
is inclined forwards, and carries the centre of gravity in 
that direction, and while one leg sustains the body, the 
other is thrown forwards to prevent it from falling, and to 
sustain it in turn. For this reason, walking has been de- 
fined to be a continual falling forwards, continually inter- 
rupted by the projection of the legs. 

186. The throwing forwards of the leg, which would re- 
quire a very considerable effort were the muscles obliged 
to sustain the weight of the limbs also, is facilitated by a 
very peculiar arrangement ; that is, the joints are perfectly 
closed, so that the pressure of the atmosphere outside is 
sufficient of itself to maintain them in place, without the 
assistance of the muscles. This may be proved by experi- 
ment. If we cut away all the muscles around the hip-joint, 
the thigh-bone still adheres firmly to the pelvis, but sepa- 
rates the moment a hole is pierced, so as to admit air into 
the socket. 

187. In ordinary walking, the advancing leg touches the 
ground just before the other is raised ; so that there is a 
moment when the body rests on both limbs. It is only when 
the speed is very much accelerated, that the two actions be- 
come simultaneous. The walking of quadrupeds is a simi- 
lar process, but with this difference, that the body always 
rests on two legs at least. The limbs are raised in a deter- 
minate order, usually in such a manner that the hind-leg of 
one side succeeds the fore-leg of the opposite side. Some 


animals, as the giraffe, the lama, and the bear, raise both 
legs of one side at the same moment. This is called 
ambling or pacing. 

188. RUNNING consists in the rapid repetition of the mo- 
tions of walking. The running of lizards and birds is 
merely an accelerated walk ; but in the horse and dog, 
and most of the mammals, a distinction is made between the 
walk, the trot, and the gallop, all of which have different 
positions or measures. The trot has but two measures. 
The animal raises a leg on each side, in a cross direction, 
that is to say, the right fore leg with the left hind leg, and so 
on. The gallop has three measures. After advancing the two 
fore-legs, one after the other, the animal raises and brings 
forward the two hind legs, simultaneously. Sometimes also, 
when the gallop is greatly urged, there are but two mea- 
sures ; the fore limbs are raised together, as well as the 
hind legs. 

189. LEAPING consists in a bending of all the limbs, fol- 
lowed by a sudden extension of them, which throws the body 
forwards with so much force as to raise it from the ground, 
for an instant, to strike it again at a certain distance in 
advance. For this purpose, the animal always crouches 
before leaping. Most animals make only an occasional use 
of this mode of progression, when some obstacle is to be 
surmounted ; but in a few instances, this is the habitual 
mode. As the hind legs are especially used in leaping, we 
observe that all leaping animals have the posterior members 
very much more robust than the anterior, as frogs, the kan- 
garoos, jerboas, and even the hares. Leaping is also com- 
mon among certain birds, especially among the sparro\vs, 
the thrushes, &c. Finally, there is also a large number of 
leaping insects, such as the flea, the large tribe of grass- 
hoppers and crickets, in which we find that pair of legs 
with which leaping is accomplished, much more developed 
than the others. 


190. CLIMBING- is merely walking upon the surface of an 
inclined or even upright object. It is more frequently ac- 
complished by means of sharp nails ; and hence many 
carnivorous animals climb with great facility, such as the 
cat tribe, the lizards ; and many birds, the woodpecker, for 
instance. Others employ their arms for this purpose, like 
the bears, when they climb a tree ; or their hands, and even 
their tails, like the monkeys ; or their beaks, like the par- 
rots. Lastly, there are some whose natural mode of pro- 
gression is climbing. Such are the sloths, with their arms 
so long, that when placed upon the ground, they move very 
awkwardly ; and yet their structure is by no means defect- 
ive, for in their accustomed movements upon trees, they 
can use their limbs with very great adroitness. 

191. Most quadrupeds can both walk, trot, gallop, and 
leap ; birds walk and leap ; lizards neither leap nor gallop, 
but only walk and run, and some of them with great rapid- 
ity. No insect either trots or gallops, but many of them 
leap. Yet their leaping is not always the effect of the mus- 
cular force of their legs, as with the flea and grasshopper ; 
but some of them leap by means of a spring, in the form of 
a hook, attached to the tail, which they bend beneath the 
body, and which, when let loose, causes them to bound to a 
great distance, as in the Podurellse. Still others leap by 
means of a spring, attached beneath the breast, which 
strikes against the abdomen when the body is bent ; as the 
spring-beetles (Elaters). 

192. FLIGHT is accomplished by the simultaneous action 
of the two anterior limbs, the wings, as leaping is by that of 
the two hinder limbs. The wings being expanded, strike and 
compress the air, which thus becomes a support, for the 
moment, upon which the body of the bird may rest itself. 
But as this support very soon yields, owing to the slight 
density of the air, it follows that the bird must make the 
greater and more rapid efforts to compensate for this dis- 


advantage. Hence it requires a much greater expenditure 
of strength to fly than to walk ; and therefore, we find the 
great mass of muscles in birds concentrated about the 
breast (Fig. 30). To facilitate its flight, the bird, after 
each flap of the wings, brings them against the body, so as 
to present as little surface to the air as possible ; for a 
still further diminution of resistance, all birds have the 
anterior part of the body very slender. Their flight 
would be much more difficult if they had large heads 
and short necks. 

193. Some quadrupeds have a fold of the skin at the 
sides, which may be extended by the legs, and which ena- 
bles them to leap from branch to branch, with more facility, 
such as the flying-squirrel and Galeopithecus. But this 
is not flight, properly speaking, since none of the pecu- 
liar operations of flight are performed. There are also 
some fishes, whose pectoral fins are so extended as to ena- 
ble them to dart from the water, and sustain themselves 
for a considerable time in the air ; and hence they are 
called flying-fish. But this is not truly flight. 

194. SWIMMING is the mode of locomotion employed 
by the greater part of aquatic animals. Most animals 
which live in the water swim with more or less facility. 
Swimming has this in common with flight, that the medium 
in which it is performed, the water, becomes also the sup- 
port, and readily yields also to the impulse of the fins. 
Only, as water is much more dense than air, and as the 
body of most aquatic animals is of very nearly the same 
weight as water, it follows that in swimming, very little 
effort is requisite to keep the body from sinking. The 
whole effort of its muscles is consequently employed in pro- 
gression, and hence swimming requires vastly less muscular 
force than flying. 

195. Swimming is accomplished by means of various or- 


gans designated under the general term,j^?i5, although in an 
anatomical point of view, these may represent very different 
parts. In the Whales, it is the anterior extremities and 
the tail which are transformed into fins. In Fishes, the pec- 
toral fins, which represent the arms, and the ventral fins, 
which represent the legs, are employed for swimming, but 
they are not the principal organs ; for it is by the tail 
or caudal fin, that progression is principally effected. 
Hence the progression of the fish is precisely that of a 
boat under the sole guidance of the sculling-oar. In the 
same manner as a succession of strokes alternately right 
and left, propels the boat straight forwards, so the fish 
advances by striking alternately right and left. If he 
wishes to advance obliquely, he has only to strike a little 
more strongly in the direction opposite to that which he 
wishes to take. The Whales, on the contrary, swim by 
striking the water up and down ; and it is the same with a few 
fishes also, such as the rays and the soles. The air- 
bladder facilitates the rising and sinking of the fish by ena- 
bling it to vary the specific weight of the body. 

196. Most land animals swim with more or less ease, by 
simply employing the ordinary motions of walking. Those 
which frequent the water, like the beaver, or which feed on 
marine animals, as the otter and duck, have webbed feet, 
that is to say, the fingers are united by a membrane, which, 
by being expanded, acts as a paddle. 

197. There is also a large number of invertebrate ani- 
mals in which swimming is the principal or the only mode 
of progression. Lobsters swim by means of their tail, and 
like the Whales, strike the water up and down. Other 
Crustacea have a pair of legs fashioned like oars ; as 
the posterior legs in Lupa, for example. Many insects, 
likewise, swim with their legs, which are abundantly fringed 
with hairs to give them surface ; as the little water boat- 



men, (Gyrinus, Dytiscus), whose mazy dances on the sum- 
mer streams every one must have observed. The cuttle- 
fish uses its long tentacles as oars (Fig. 47) ; and some 
star-fishes (Comatula, Euryale), use their arms with great 
adroitness. Finally, there are some insects, which have 
their limbs constructed for running on the surface of water, 
as the water-spiders. (Ranatra, Hydrometra). 

Pig. 47. 

198. A large number of animals have the faculty of 
moving both in the air and on land, as is the case with 
most birds, and a large proportion of insects. Others move 
with equal facility, and by the same members, on land and in 
water, as some of the aquatic birds and most of the reptiles. 
The latter have even received the name Amphibia, on this 
account. Finally, there are some which both walk, fly 
and swim, as the ducks and water hens ; but, on the other 
hand, they do not excel in either mode of progression. 

199. However different may appear to us the movements 
and offices performed by the limbs, according to the element 
in which they act, we see that they are none the less the 
effect of the same mechanism. The contraction of the 
same set of muscles, causes the leg of the stag to bend for 
leaping, the wing of the bird to flap in the air, the arm of 
the mole to excavate the earth, and the fin of the whale 
to strike the water. 



200. THE second class of the functions of animal life 
are those which relate to the maintenance of life and the 
perpetuation of the species ; the functions of vegetative 
life (59). 

201. The increase of the volume of the body must re- 
quire additional materials. There is also an incessant waste 
of particles which, having become unfit for further use, 
are therefore carried out of the system. Every contraction 
of a muscle expends the energy of some particles, whose 
place must be supplied. These supplies are derived from 
every natural source, the animal, vegetable, and even the 
mineral kingdoms ; and are received under every variety of 
solid, liquid, and gaseous form. Thus, there is a perpetual 
interchange of substance between the animal body and the 
world around. The conversion of these supplies into a 
suitable material, and the appropriation of it to the growth 
and sustenance of the body, is called NUTRITION. 

202. In early life, during the period of growth, the 
amount of substances received is greater than that which is 
lost. At a later period, when growth is completed, an equi- 
librium between the matters received and those rejected, is 
established. At a still later period, the equilibrium is again 
disturbed, more is rejected than is retained, decrepitude be- 
gins, and at last the organism becomes exhausted, the func- 
tions cease, and death ensues. 



203. The solids and fluids taken into the body as food 
are subjected to a process called Digestion, by which the 
solid portions are also reduced to a fluid state, the nutritive 
separated from the excrementitious, and the whole is pre- 
pared to become blood, bone, muscle, &c. The residue 
is afterwards expelled, together with those particles of the 
body which require to be renewed, and those \vhich have 
been derived from the blood by several processes, termed 
Secretions. Matters in a gaseous form are also received 
and expelled with the air we breathe, by a process 
called Respiration. The nutritive fluids are conveyed 
to every part of the body by currents, usually confined in 
vessels, and which, as they return, bring back the particles 
which are to be either renovated or expelled. This circuit 
is what is termed the Circulation. The function of Nutri- 
tion, therefore, combines several distinct processes. 



204. DIGESTION, or the process by which the nutritive 
parts of food are elaborated and 

prepared to become blood, is ef- 
fected in certain cavities, the stom- 
ach and intestines, or alimentary 
canal. This canal is more or less 
complicated in the various classes 
of animals ; but there is no animal, 
however low its organization, which 
has not a stomach, (54). 

205. In the polypi, the digestive 

apparatus is limited to a single cav- Fig. 48. 

ity. In the Sea Anemone (Actinia), for example, it is a 
pouch (Fig. 48, b), suspended in the interior of the body. 




When the food has been sufficiently digested there, it passes 
into the general cavity of the body (c), which is filled with 
water, and mingling with it, flows thence into all parts 

of the animal. The jelly-fishes (Medusse), 
and some Worms have a distinct stomach, 
with appendages branching off in every di- 
rection (Fig. 31), in which a more com- 
plete elaboration takes place. The little 
worms known by the name of Planaria 
present a striking example of these rami- 
fications of the intestine (Fig. 49, e). But 
here likewise, the product of digestion, 
namely, the chyle, mingles with the fluids 
of the cavity of the body which surround 
the intestine (d] and its branches, and cir- 
culation is not yet distinct from diges- 

Fig. 49. tion. 
206. As we rise in the scale of animals, the functions 
concerned in nutrition become more and more distinct from 
each other. Digestion and circulation, no longer confounded, 
are accomplished separately, in distinct cavities. The most 
important organs concerned in di- 
gestion are the stomach, and the 
small and large intestine. The 
first indications of such a distinc- 
tion are perceived in the higher 
Radiata, such as the sea-urchins 
(Fig. 50), in which the stomach (s), 
is broader than either extremity of 
the intestine. The dimensions and 
form of the intestinal cavities vary Fig. so. 

considerably according to the mode of life of the animal ; 
but the special functions assigned to them are invariable ; 
and the three principal cavities succeed each other, in every 
animal where they are found, in an invariable order ; first, 




the stomach (5), then the intestine, which is small at first, 

but often enlarged to- 
wards its termination. 
This arrangement may 
be seen by the following 
diagrams from a beetle, 
and a land-mollusk, where 
the same letters indicate 
corresponding parts (Figs. 
51, 52). 

207. From the mouth, 
the food passes into the 
stomach through a narrow 
tube in the neck, called 
the cesophagus or gullet 
(o). This is not always a 

Fisr. 51. 

Fig. 52. 

direct passage of uniform size ; but there is sometimes a 
pouch, the crop (c), into which the food is first introduced, 
and which sometimes acquires considerable dimensions, espe- 
cially in birds, and in some insects andmollusks (Fig. 51). In 
the stomach, the true digestive process is begun. The food no 
sooner arrives there than changes commence, under the influ- 
ence of a peculiar fluid called the gastric juice, which is se- 
creted by the glands lining the interior of the stomach. The 
digestive action is sometimes aided by the movements of 
the stomach itself, which, by its strong contractions, tritu- 
rates the food. This is especially the case in the gizzard 
of some birds, which, in the hens and ducks, for instance, is 
a powerful muscular organ. In some of the Crustacea and 
Mollusks, as the Lobster and Aplysia, there are even solid 
organs for breaking down the food within the stomach itself. 
208. The result of this process is the reduction of the 
food to a pulpy fluid called chyme, which varies in its 
nature with the food. Hence the function of the stomach 
has been named chymification. The chyme thus formed 



is transferred to the intestine, by a peculiar movement like 
that of a worm in creeping, which has accordingly received 
the name of vermicular or peristaltic motion. 

209. The form of the small intestine is less variable than 
that of the stomach. It is a narrow tube with thin walls, 
coiled in various directions in the vertebrate animals, but 
more simple in the invertebrates, especially the insects. Its 
length varies according to the nature of the food, being in 
general longer in herbivorous than in carnivorous animals. 
In this portion of the canal, the aliment undergoes its 
complete elaboration, through the agency of certain juices 
which here mingle with the chyme, such as the bile secreted 
by the liver, and the pancreatic juice secreted by the 
pancreas. The result of this elaboration is to produce a 
complete separation of the truly nutritious parts, in the 
form of a milky liquid called chyle. The process is called 

210. The chyle is composed of minute, colorless globules, 

of a somewhat flattened form (Fig. 53). It 
is taken up and carried into the blood by 
means of very minute vessels, called lym- 
\phatic vessels or lacteals, which are distri- 
buted everywhere in the walls of the intestine, 
and communicate with the veins, forming also 
in their course several glandu- 
lar masses, as seen on the por- 
tion of intestine connected with a 
vein (Fig. 54). The residue 
passes on to the large intestine, 
from whence it is expelled in 
the form of excrement. 

211. These organs constitute 
the essential apparatus for diges- 
. 54. tion ; but there are, in the higher 

animals, several additional ones for aiding in the reduction of 

Fig. 53. 



the food to chyle which render their digestive apparatus 
quite complicated. In the first place, hard parts, of a horny 
or bony texture, are usually placed ahout the mouth of 
those animals that feed on solid substances, which serve 
for cutting or bruising the food into small fragments before 
it is swallowed ; and, in many of the lower animals, these 
organs are the only hard portions of the body. This pro- 
cess of subdividing or chewing the food, is termed masti- 

212. Beginning with the Radiata, we find the apparatus 
for mastication partaking of the star-like arrangement which 

Fig. 55. Fig. 56. 

characterizes those animals. Thus, in Scutella (Fig. 55), 
we have a pentagon composed of five triangular jaws, con- 
verging at their summits towards a central aperture which 
corresponds to the mouth, each one bearing a plate or tooth, 
like a knife-blade, fitted by one edge into a cleft. The five 
jaws move towards the centre, and pierce or cut the objects 
which come between them. In some of the sea-urchins, 
(Echinus), this apparatus, which has been called Aristotle's 
lantern (Fig. 56), consists of numerous pieces, and is 
much more complicated. Still, the five fundamental pieces 
or jaws, each of them bearing a tooth at its point, may be 
recognized as in Scutella ; only instead of being placed hori- 
zontally, they form an inverted pyramid. 




213. Among the Mollusks, a few, like the cuttle-fishes, 
have solid jaws or beaks closely resem- 
bling the beak of a parrot 
(Fig. 57) ; and they move 
up and down as in birds. 
But a much larger number 


rasp their food by means of 
a tongue coiled like a watch- 

Fig. 58. 

Fig. 57. 

spring, the surface of which is covered with innumerable 
minute tooth-like points of a horny consistence, as in the 
highly magnified portion of the tongue of Natica (Fig. 58). 
214. The Articulata are remarkable, as a class, for the 
diversity and complication of their apparatus for taking and 

dividing their food. In some marine worms, 
Nereis, for example, the jaws consist of a 
pair of curved, horny instruments, lodged in 
a sheath (Fig. 59). In spiders, these jaws 
are external, and sometimes mounted on 
Fig. 59. long, jointed stems. Insects which masti- 
cate their food have, for the most part, at least two pairs 
of horny jaws (Fig. 60, 61, w), besides several additional 
pieces which serve for seizing and holding their food. 
Those which live on the fluids which they extract either 
from plants or from the blood of other animals, have the 
masticatory organs transformed into a trunk or tube for this 
purpose. This trunk is sometimes rolled up in a spiral 
manner, as in the butterfly (Fig. 64) ; or it is stiff, and 



Fig. 61. Fig. 62. Fig. 63. 

Fig. 64. 

folded beneath the chest, as in the squash-bugs (Fig. 62), 



and contains several piercers of extreme delicacy, (Fig. 63), 
adapted to penetrate the skin of animals or other objects 
whose juices they extract ; or they are prolonged so as to 
shield the tongue when thrust out in search of nutritive 
juices, as in the bees (Fig. 61.) The crabs have their 
anterior feet transformed into a kind of jaws. Indeed, 
even down to the microscopic Rotifers, we find veiy 
complicated jaws, as seen in the interior of Brachionus 

Fig. 65. 

Fig. 66. 

(Fig. 65), and represented largely magnified in Fig. 66. 
But amidst this diversity of apparatus, there is one thing 
which characterizes all the Articulata, namely, the jaws all 
move sideways ; while those of the Vertebrates move up and 
down, and those of the Radiata move concentrically. 

215. In the Vertebrates, the jaws form a part of the bony 

skeleton. In most of them the 
lower jaw only is movable, and 
is brought up against the upper 
'jaw by means of very strong mus- 
cles, the temporal and masseter 
Fig. 67. muscles (Fig. 67, , m), which per- 

form all the motions requisite for seizing and masticating food. 

216. The jaws are usually armed 
with solid cutting instruments, the 
TEETH, or else enveloped in a horny 
covering, the leak, as in the birds and 
tortoises (Fig. 68). In some of the 

whales, we have instead, a range of Fig. 68. 



long, flexible, horny plates or fans, fringed at the margin, 
which serve as strainers to separate the minute marine ani- 
mals on which they 
feed, from the water 
drawn in with them 
(Fig. 69). A few are 
entirely destitute of 
teeth, as the ant-eater 
(Fig. 70). 

217. Though all the 
Fig. 69. vertebrates possess jaws, 

it must not be inferred that they all chew their food. 
Many of them swallow their prey whole ; as most birds, 
tortoises, and whales. Even those which are furnished 
with teeth do not all of them masticate their food ; some 
use them merely for seizing and securing their prey, as 
we find in the lizards, frogs, crocodiles and the great 
majority of fishes. In such animals, it has been remarked 
that the teeth are nearly all alike in form and structure, as 

Fisr. 71. 

Fig. 72. 

for instance in the alligator (Fig. 71) ; and in most fishes. 
A few of the latter, some of the Rays, for example, have 
a sort of bony pavement (Fig. 72), composed of a peculiar 



kind of teeth, with which they crush the shells of the 
mollusks on which they feed. 

218. The Mammals, however, are almost the only verte- 
brates which can be properly said to masticate their food. 
Their teeth are well developed, and present great diversity 
in form, arrangement and mode of insertion. Three kinds 
of teeth are usually distinguished in most of these ani- 
mals, whatever may 
be their mode of life ; 
namely, the cutting 
teeth, incisors ; the 
tusks or carnivorous 
teeth, canines ; and 
the grinders, molars 
(Fig. 73). The in- 
cisors (a) occupy the 
front of the mouth ; 
they are the most simple and the least varied ; they have 
a thin cutting summit, and are employed almost exclu- 
sively for seizing food ; except in the elephant, in which 
they assume the form of large tusks. The canines (b) are 
conical, more prominent than the others, more or less 
curved, and only two in each jaw. They have but a single 
root, like the incisors, and in the carnivora become very 
formidable weapons. In the herbivora, they are entirely 
wanting, or when existing they are so enlarged and modi- 
fied as also to become powerful organs of offence and 
defence, although useless for mastication ; as in the baby- 
roussa, &c. The molars (c) are the most important for 
indicating the habits and internal structure of the animal ; 
and at the same time they are most varied in shape. 
Among them we find every transition, from those of a 
sharp and pointed form, as in the cat tribe, to those with 
broad and level summits, as in the ruminants and rodents. 

Fig. 73. 



Still, they have one constant character, namely, their roots 
are never simple, but double or triple, which not only 
fixes them more firmly, but prevents them from being 
driven into the jaw in the efforts of mastication. 

219. The harmony of organs already spoken of (22 -24) 
is illustrated, in a most striking manner, by the study 
of the teeth of the mammals, and especially of their molar 
teeth. So constantly do they correspond with the struc- 
ture of the other parts of the body, that a single molar 
is sufficient not only to indicate the mode of life of the ani- 
mal from which it was obtained, and to show whether it 
fed on flesh or vegetables, but also to determine the particu- 
lar group to which it belongs. Thus, those beasts of prey 
which feed on insects, and which on that account have been 

Fig. 74. 

Fig. 76. Fig. 75. 

called Insectivora, such as the moles and bats, have the mo- 
lars terminated by several sharp, conical points (Fig. 74), 
so arranged that the elevations of one tooth fit exactly into 
the depressions of the tooth opposite to it. In the true Car- 
nivora (Fig. 75), on the contrary, the molars are com- 
pressed laterally, so as to produce a sharp cutting edge ; 
and they shut by the side of each other, like the blades of 
scissors, thereby dividing the food with great facility. 

220. The same adaptation is observed in the teeth of 
herbivorous animals. Those which chew the cud (rumi- 
nants), many of the thick skinned animals (pachydermata), 


like the elephant, and some of the gnawers (rodentia), 
like the hare (Fig. 76), have the summits of the molars 
flat, like millstones, for grinding the grass and leaves 
on which they subsist. Finally, the omnivora, those which 
feed on both flesh and fruit, like man and the monkeys, 
have the molars terminating in several rounded tubercles, 
being thus adapted to the mixed nature of their food. 

221. Again, the mode in which the molars are combined 
with the canines and incisors furnishes excellent means of 
characterizing families and genera. Even the minute struc- 
ture of a tooth is so peculiar in each group of animals, 
and yet is subject to such invariable rules, that it is possible 
to decide positively the structure of an animal, merely by 
the inspection of the fragment of a tooth under the micro- 

222. Another process, subsidiary to digestion, is called 
insalivation. Animals which masticate their food have 
glands, in the neighborhood of the mouth, which secrete a 
fluid called saliva. This fluid mingles with the food as it is 
chewed, and prepares it also to be more readily swallowed. 
The salivary glands are wanting in all animals which swal- 
low their food without mastication. When the food is mas- 
ticated and mingled with saliva, it is carried back by 
the tongue, and passes down a tube, the oesophagus, into 
the stomach. This act is called deglutition or swal- 

223. The wisdom and skill of the Creator is strikingly illus- 
trated in the means he has afforded to every creature for se- 
curing the means of its subsistence. Some animals have no 
ability to move from place to place, but are fixed to the soil ; 
as the oyster, the polypi, &c. These are dependent for sub- 
sistence upon such food as may stray or float near, and they 
have the means of securing it when it comes within their 
reach. The oyster closes its shell, and thus secures its prey ; 


the polyp has flexible arms (Fig. 77), capable of great exten- 
sion, which instantly embrace any minute ani- 
mal that comes in contact with them. The 
cuttle-fish also, has similar arms about the 
mouth, furnished with ranges of suckers, by 
which it secures its prey (Fig. 47). 

224. Some are provided with instruments 
for extracting food from places which would 

be otherwise inaccessible. Some of the Fig. 77. 
mollusks, with their rasp-like tongue (Fig. 58), perforate 
the shells of other animals, and thus reach and extract 
the inhabitant. Insects have various piercers, suckers, or a 
protractile tongue for the same purpose (Figs. 61-64). 
Many of the Annelides, the leeches for example, have a 
sucker, which enables them to produce a vacuum, and 
thereby draw out blood from the perforations they make. 
Many microscopic animals are provided with hairs or cilia 
around the mouth (Fig. 65), which by their incessant 
motion produce currents that bring within reach the 
still more minute creatures or particles on which they 

225. Among the Vertebrata, the herbivora generally 
employ their lips or their tongue, or both together, for seiz- 
ing the grass or leaves they feed upon. The carnivora 
use their jaws, teeth, and especially their claws, which 
are long, sharp and movable, and admirably adapted for 
the purpose. The woodpeckers have long, bony tongues, 
barbed at the tip, with which they draw out insects from 
deep holes and crevices. Some reptiles also use their 
tongue to take their prey. Thus, the chameleon obtains 
flies at a distance of three or four inches, by darting out 
his tongue, the enlarged end of which is covered with a 
glutinous substance to which they adhere. The elephant, 
whose tusks and short neck prevent him from bringing his 


mouth to the ground, has the nose prolonged into a trunk, 
which he uses with great dexterity, for bringing food and 
drink to his mouth. Doubtless the mastodon, once so abun- 
dant in this country, was furnished with a similar organ. 
Man and the monkeys employ the hand exclusively, for 

226. Some animals drink by suction, like the ox, others 
by lapping, like the dog. Birds simply fill the beak with 
water, then raising the head, allow it to run down into the 
crop ; some of them, however, suck up liquids, like the 




227. THE nutritive portions of the food are poured into 
the blood or the general mass of fluid which pervades every 
part of the body, and out of which every tissue is origi- 
nally constructed, and from time to time renewed. 

228. The Blood, when examined by the microscope, is 
found to consist of a transparent fluid, the serum, in which 
float many rounded, somewhat compressed bodies, called 
globules. These globules vary in number with the natural 
heat of the animal from which the blood is taken. Thus, 
they are more numerous in birds than in the mammals, and 

Fig. 79. 

Fig. 80. 

Fig. 81. 

Fig. 78. 

more abundant in the latter than in fishes. In man and 
other mammals they are very small and nearly circular 
(Fig. 78) ; they are somewhat larger and of an oval form 
in birds and fishes (Figs. 79, 81) ; and still larger in rep- 
tiles (Fig. 80). 

229. The color of the blood in the vertebrates is bright 
red ; but in some invertebrates, as in the crabs and mol- 
lusks, it is nearly or quite colorless ; while in the worms 


and some echinoderms, it is variously colored yellow, 
orange, red, violet, lilac, and even green. 

230. The presence of this fluid in every part of the 
body is one of the essential conditions of animal life. A 
perpetual current flows from the digestive organs towards 
the remotest parts of the surface ; and such portions as are 
not required for nutriment return, mingled with those which 
have become useless and need to be renewed or expelled. 
The blood is kept in an incessant CIRCULATION for this 

231. In the lowest animals, such as the polypi, the nutri- 
tive fluid is merely the products of digestion mingled with 
water in the common cavity of the viscera, with which it 
comes in immediate contact, as well as with the whole 
interior of the body. In the jelly-fishes, which occupy a 
somewhat higher rank, a similar liquid is distributed by pro- 
longations of the principal cavity to different parts of the 
body (Fig. 31). Currents are produced in these, partly by 
the general movements of the animal, and partly by means 
of the incessant vibrations of microscopic hairs which over- 
spread the interior, and are hence called vibratile cilia. In 
most of the mollusks and insects, the blood is also in imme- 
diate contact with the viscera ; or the vessels, if any, are 
not continuous, but terminate in various cavities. 

232. In animals of still higher organization, as the verte- 
brates, the mollusks, and a part of the articulata and 
echinoderms, we find the vital fluid enclosed in an appro- 
priate set of vessels, by which it is successively con- 
veyed throughout the system to supply its wants, and to the 
respiratory organs, where it absorbs oxygen, or in other 
words, becomes oxygenated. 

233. The vessels in which the blood circulates are of 
two kinds : 1. The arteries, of a firm, elastic structure, 
which may be distended or contracted, according to the 


volume of their contents, and which convey the blood from 
the centre towards the surface, distributing it to every 
point of the body ; 2. The veins, of a thin, mem- 
branous structure, furnished within with valves, 
(Fig. 82, v), which aid in sustaining the column 
of blood, and allow it to flow towards the 
centre only. The arteries constantly subdivide 
into smaller and smaller branches ; while the 
veins commence in minute twigs, and are gath- 
ered into branches and larger trunks to unite final- 
ly at the centre. 

234. The extremities of the arteries and veins are con- 

r +. nected by a net-work of extremely 
iff minute and delicate vessels, called 
capillary vessels (Fig. 83). They 
77 pervade every portion of the body, 
so that almost no point can be pricked 
Fig. 83. from which blood will not issue. 

Notwithstanding their minuteness, the most important pro- 
cesses of nutrition are performed by these vessels, such as 
the removal of effete particles and the substitution of new 
ones, and all those changes by which the bright blood of the 
arteries becomes the dark blood of the veins ; and again, in 
the capillaries of the respiratory organs, the dark venous 
blood is oxygenated and restored to the bright scarlet hue of 
the arterial blood. 

235. Where there are blood-vessels in the lowest animals 
the blood is kept in motion by 

the occasional contraction of 

some of the principal vessels, as 

in the worms. Insects have a 

large vessel running along the 

back, furnished with valves so 

arranged that, when the vessel pig. 34. 

contracts, the blood can flow only towards the head, and 




being thence distributed to the body, is returned again into 
the dorsal vessel (Fig. 83), by fissures at its sides. 

236. In all the higher animals there is a central organ, 
the heart, which forces the blood through the arteries to- 
wards the surface, and receives it again on its return. 
The HEART is a hollow muscular organ of a conical 
form, which dilates and contracts at regular intervals, inde- 
pendently of the will. It is either a single cavity, or is di- 
vided by walls into two, three, or four compartments, as 
seen in the following diagrams. These modifications are 
important in their connection with the respiratory organs, and 
indicate the higher or lower rank of an animal, as determined 
by the quality of the blood distributed in those organs. 

237. In the mammals and birds the heart is divided by 
a vertical partition into two cavities, each of which is 
again divided into two compartments, one above the other 
(Fig. 85). The two upper cavities are called auricles, and 
the lower ones are called ventricles. Reptiles have two 

Fig. 85. 

Fig. 86. 

Fig. 87. 

auricles and one ventricle (Fig. 86). Fishes have one auri- 
cle and one ventricle only (Fig. 87). 

238. The auricles do not communicate with each other, 
nor do the ventricles. The former receive the blood 
from the body and from the respiratory organs, and each 
auricle sends it into the ventricle beneath, through an 
opening guarded by a valve, to prevent its reflux ; while 
the ventricles, by their contractions, force the blood through 
the arteries into the lungs and through the body generally. 



239. The two auricles dilate at the same instant, and also 
contract simultaneously ; so also do the ventricles. These 
successive contractions and dilatations constitute the pul- 
sations of the heart. The contraction is called systole, 
and the dilatation is called diastole. Each pulsation con- 
sists of two movements, the diastole or dilatation of the 
ventricles, during which the auricles contract, and the systole 
or contraction of the ventricles, while the auricles dilate. 
The frequency of the pulse varies in different animals, and 
even in the same animal, according to age, sex, and the de- 
gree of health. In adult man, they are commonly about 
seventy beats per minute. 

240. The course of the blood in those animals which 
have four cavities to the heart is as follows, beginning with 
the left ventricle (Fig. 85, lv}. By the contraction of this 
ventricle, the blood is driven through the main arterial 
trunk, called the aorta (Fig. 90, a), and is distributed by its 
branches throughout the body ; it is then collected by the 
veins, carried back to the heart, and poured into the right 
auricle (Fig. 85, ra), which sends it into the right ventricle 
(rv). The right ventricle propels it through another set of 
arteries, the pulmonary arteries (Fig. 90, p), to the lungs (Z) ; 
it is there collected by the pulmonary veins, and conveyed 
to the left auricle (Fig. 85, la), by which it is returned to the 
left ventricle, thus completing the circuit. 

241. Hence the blood in performing its whole circuit 
passes twice through the heart. The first part of this cir- 
cuit, the passage of the blood through the body, is called 
the great circulation ; and the second part, the passage 
of the blood through the lungs, is the lesser or pulmonary 
circulation : this double circuit is said to be a complete 
circulation. In this case the heart may be justly re- 
garded as two hearts conjoined, and in fact the whole of 
the lesser circulation intervenes in the passage of the blood 


from one side of the heart to the other ; except during the 
embryonic period, when there is an opening between the 
two auricles, which closes as soon as respiration commences. 

242. In reptiles (Fig. 86), the venous blood from the body 
is received into one auricle, and the oxygenated blood from 
the lungs into the other. These throw their contents into the 
single ventricle below, which propels the mixture in part to 
the body, and in part to the lungs ; but as only the smaller 
portion of the whole quantity is sent to the lungs in a 
single circuit, the circulation is said to be incomplete. In 
the Crocodiles, the ventricle has a partition which keeps 
separate the two kinds of blood received from the auricles ; 
but the mixture soon takes place by means of a special 
artery which passes from the pulmonary artery to the aorta. 

243. In fishes (Fig. 87) the blood is carried directly from 
the ventricle to the gills, which are the respiratory organs ; 
whence it passes into the arteries for distribution to the sys- 
tem in general, and returns by the veins to the auricle. 
Here the blood, in its circuit, passes but once through the 
heart ; but the heart of a fish corresponds nevertheless to 
the heart of a mammal, and not to one half of it, as has 
often been maintained. 

244. Crabs and other Crustacea have but a single ventri- 
cle without an auricle. 

In the mollusks there is 
likewise but a single 
ventricle, as in Natica 
(Fig. 88, h). Some have 
in addition one or two 
auricles. These auricles 
are sometimes so dis- Fi - 88 ' 

joined as to form so many isolated hearts, as in the cuttle- 
fish. Among Radiata, the sea-urchins are provided with 
a tubular heart. 



245. FOR the maintenance of its vital properties, the 
blood must be submitted to the influence of the air. This 
is true of all animals, whether they live in the atmosphere 
or in the water. No animal can survive for any considera- 
ble period of time without air ; and the higher animals 
almost instantly die when deprived of it. It is the office of 
RESPIRATION to bring the blood into communication with 
the air. 

246. Among animals which breathe in the open 
air, some have a series of tubes branch- 
ing through the interior of the body, 

called trachece (Fig. 89, ), and opening 
externally upon the sides of the body, 
by small apertures, called stigmata (s) ; as 
in the insects and in some spiders. But 
the most common mode of respiration is 
by means of the LUNGS, a pair of peculiar 
spongy or cellular organs, in the form 
of large pouches, which are the more 
complicated in proportion to the quantity 
of air to be consumed. 

247. In the lower vertebrata provided with lungs there is 
a single organ ; but in the higher classes they are in pairs, 
placed in the cavity formed by the ribs, one on each side of 

Fig. 89. 



Fig. 90. 

the vertebral column, and enclosing the heart (h) between 
them (Fig. 90, / Z). The lungs communicate with the atmo- 
sphere by means of a tube composed of cartilaginous 
rings which arises from the back part of the mouth, and 
divides below, first into a branch for each organ, and then 
into innumerable branches penetrating 
their whole mass, and finally termina- 
ting in minute sacs. This tube is the 
trachea onvindpipe (w),and its branches 
are the bronchi. In the higher air- 
breathing animals the lungs and heart 
occupy an apartment by themselves, 
the chest, which is separated from the 
other contents of the lower arch (161), 
by a fleshy partition, called the dia- 
phragm, passing across the cavity of the 
body, and arching into the chest. The only access to this 
apartment is by the glottis (Fig. 22, o) through the trachea. 

248. The mechanism of respiration by lungs may be 
compared to the action of a bellows. The cavity of the 
chest is enlarged by raising the ribs, the arches of which 
naturally slope somewhat downward, but more especially by 
the contraction of the diaphragm, whereby its intrusion into 
the chest is diminished. This enlargement causes the air to 
rush in through the trachea, distending the lung so as to 
fill the additional space. When the diaphragm is again re- 
laxed, and the ribs are allowed to subside, the cavity is 
again diminished, and the air expelled. These movements 
are termed inspiration or inhalation, and expiration. The 
spongy pulmonary substance being thus distended by air, 
the blood sent from the heart is brought into such contact 
with it as to allow the requisite interchange to take 
place (235). 

249. The respiration of animals breathing in water is ac- 


complished by a different mechanism. The air is to be 

derived from the water, in which 
more or less is always diffused. 
The organs for this purpose are 
91- called branchi<z or gills, and are 

either delicate tufts or plumes floating outside of the body, 
as in some of the marine worms 
(Fig. 33), and many mollusks (Fig. 
91, g] ; or they consist of deli- 
cate folds, as in fishes (Fig. 92), 
crabs and most mollusks (Fig. 88, g}. 
These gills are always so situated 
that the water has free access to Fig. 92. 

them. In the lower aquatic animals, such as the polypi, 
jelly-fishes and some mollusks, respiration is facilitated 
by the incessant motions of vibratory cilia, which line 
the respiratory organs as well as other portions of the sur- 
face of the body ; the currents they produce bringing 
constantly fresh supplies of water containing air in contact 
with the respiratory organs. 

250. Many animals living in water, however, rise to the 
surface and breathe the atmosphere there, or are furnished 
with the means of carrying away a temporary supply of air. 
This is the case with the whale tribe, many insects and 

251. The vivifying power of the air upon the blood is due 
to its oxygen. If an animal be confined for a time in a 
closed vessel, and the contained air be afterwards ex- 
amined, a considerable portion of its oxygen will have 
disappeared, and another gas of a very different character, 
namely, carbonic acid gas, will have taken its place. 
The essential office of respiration is to supply oxygen to 
the blood, whereby also carbon is removed from it. 

252. An immediately obvious effect of respiration in the 


red-blooded animals is a change of color. The blood in 
passing through the respiratory organs, being changed from 
a very dark purple to a bright scarlet. In the great circula- 
tion (241) the scarlet blood occupies the arteries, and is usu- 
ally called red Hood, in contradistinction from the venous 
blood, which is called Hack Hood. In the lesser circulation, 
on the contrary, the arteries carry the dark, and the veins 
the red blood. 

253. The quantity of oxygen consumed by various ani- 
mals in a given time has been accurately ascertained by 
experiment. It has been found, for instance, that a common- 
sized man consumes, on an average, about 150 cubic feet in 
twenty-four hours ; and as the oxygen constitutes but 21 per 
cent, of the atmosphere, it follows that he inhales, during a 
day, about 700 cubic feet of atmospheric air. In birds, the 
respiration is still more active, while in reptiles and fishes it 
is much more sluggish. 

254. The energy and activity of an animal correspond 
with the activity of its respiration. Thus the toad, whose 
movements are very sluggish, respires much more slowly 
than the mammals, birds, and even insects ; and it has been 
ascertained that a butterfly, notwithstanding its comparatively 
diminutive size, consumes more oxygen than a toad. 

255. The circulation and respiration have a reciprocal in- 
fluence upon each other. If the heart be powerful, or if 
violent exercise demand a more rapid supply of blood to 
repair the consequent waste (201), respiration must be 
proportionally accelerated to supply air to the greater 
amount of blood sent to the lungs. Hence the panting 
occasioned by running or other unusual efforts of the 
muscles. On the other hand, if respiration be hurried, the 
blood being rendered more stimulant by greater oxygena- 
tion, causes an acceleration of the circulation. The quan- 
tity of air consumed varies therefore with the proportion of 
the blood which is sent to the lungs. 


256. The proper temperature of an animal, or what is 
termed ANIMAL HEAT, depends on the combined activity of 
the respiratory and circulating systems, and is in direct pro- 
portion to it. In many animals the heat is maintained at a 
uniform temperature, whatever may be the variations of 
the surrounding medium. Thus, birds maintain a tempera- 
ture of about 108 Fahrenheit ; and in a large proportion 
of mammals it is generally from 95 to 105. These bear 
the general designation of warm-Hooded animals. 

257. Reptiles, fishes, and most of the still lower animals, 
have not this power of maintaining a uniform temperature. 
The heat of their body is always as low as from 35 to 50, 
but varies perceptibly with the surrounding medium, being 
however, often a little above it when the external tempera- 
ture is very low, though some may be frozen without the 
loss of life. For this reason they are denominated cold- 
Hooded animals ; and all of them have such a structure of 
the heart, that only a part of the blood which enters it is 
sent to the respiratory organs (243). 

258. The production of animal heat is obviously con- 
nected with the respiratory process. The oxygen of the 
respired air is diminished, and carbonic acid takes its 
place. The carbonic acid is formed in the body by the 
combination of the oxygen of the air with the carbon of 
the blood. The chemical combination attending this func- 
tion is therefore essentially the same as that of combustion. 
It is thus easy to understand how the natural heat of an animal 
is greater, in proportion as respiration is more active. How 
far nutrition in general, and more particularly assimilation, 
by which the liquid parts are fixed and solidified, is con- 
nected with the maintenance of the proper temperature of 
animals, and its uniform distribution through the body, has 
not yet been satisfactorily ascertained. 

259. Some of the higher warm-blooded animals do not 


maintain their elevated temperature during the whole year ; 
but pass the winter in a sort of lethargy called HIBERNATION, 
or the hibernating sleep. The marmot, the bear, the bat, 
the crocodile and most reptiles, furnish examples. During 
this state the animal takes no food ; and as it respires only 
after very prolonged intervals, its heat is diminished, and its 
vital functions generally are much reduced. The structural 
cause of hibernation is not ascertained ; but the phenomena 
attending it fully illustrate the laws already stated (254-8). 
260. There is another point of view in which respiration 
should be considered, namely, with reference to the specific 
gravity of animals, or their power of rising in the atmo- 
sphere, and of living at different depths in the water, under 
a diminished or increased pressure. The organs of respira- 
tion of birds and insects are remarkably adapted for the pur- 
pose of admitting at will a greater quantity of air into their 
body, the birds being provided with large pouches extending 
into the abdominal cavity and into the bones of the wing ; 
whilst in insects the whole body is penetrated by air tubes 
enlarged at intervals into wider cells. Aquatic animals are 
all provided with minute, almost microscopic water-tubes, 
penetrating from the surface into their substance, or 
the cavity, by which the body is adapted to pressures 
which otherwise would crush the animal. In fishes, these 
water-tubes penetrate through the bones of the skull, and 
through skin and scales; in mollusks they are more nu- 
merous in the fleshy parts, as for example, in the foot ; 
in echinoderms they pass through the skin, and even 
through the hard shell, whilst in polyps they perforate the 
walls of the general cavity of the body. 




261. WHILE the body is assimilating foreign substances 
for its nutrition and growth, it is also freeing itself from 
other substances which have become useless (201). The 
different processes for effecting this latter object are called 

262. In this operation the skin is largely concerned. Be- 
ing the outermost envelop of the body, and designed to pro- 
tect it from external influences, it is the seat of continual 
loss and reparation. New membranes and new tissues are 
constantly forming, while the old ones are removed. This 
removal is sometimes gradual and continual, in the form of 
slime, as in the fishes and most of the mollusks, their mucus 
being in fact a collection of cells detached from the surface 
of the skin ; and sometimes periodical, when it constitutes 
moulting. Thus, the mammals cast their hair, the birds 
their feathers, the serpents their outer skin, the crabs their 
test, the caterpillars their outer envelop with the hairs arising 
from it. 

263. We shall hereafter see that the skin presents such 
varieties of composition in the different groups of the Ani- 
mal Kingdom as to furnish excellent distinctions for species, 
genera, and even families. In the vertebrates it is com- 
posed of three very distinct layers of unequal thickness, as 


may be seen by Fig. 94, which represents a magnified sec- 
tion of the human skin traversed by the sudoriferous canals. 
The lower layer or the leather (a) is the thickest ; it covers 
the muscles, from which it is separated by a bed of fat 
in which the glands of transpiration are situated. Above the 
leather is a thinner layer, the vascular layer (Z), so called 
from the abundance of blood vessels it contains ; it is also 
traversed by numerous nerves, which render it very sensi- 
tive. The third or superficial layer is called epidermis (c). 
It contains neither nerves nor blood vessels, and conse- 
quently is insensible. The scales of reptiles, the nails of 
mammals, and the solid envelops of the Crustacea are merely 
indurated products of the epidermis. On the other hand, 
the feathers of birds and the scales of fishes belong to the 
vascular layer. 


264. Besides these general functions of the skin, nature 
has provided several other means for carrying out of the 
system the superfluous parts, the most important of which 
are exhalation and secretion. We have already seen (37) 
that there is a general property of all animal tissues, called 
endosmosis and exosmosis, by which they may be traversed 
by liquids and gases. The blood vessels, especially the 
capillary vessels, share this property of permeability to 
liquids. Hence, while the circulation goes on, portions of 
the circulating fluid, especially its watery parts, escape 
through the walls of the vessels, and pass off at the 
surface. This superficial loss, termed exhalation, is most 
active where vessels most abound, and accordingly most 
copious from the surface of the lungs. It has been esti- 
mated that, under certain circumstances, the human body 
loses, by exhalation, five eighths of the whole weight 
of substances taken into it. 

265. SECRETION is a more complicated process than ex- 
halation. It is not a mere mechanical operation, but is ac- 



complished by means of peculiar organs, called glands ; 
which elaborate peculiar juices, such as the sweat, the 
tears, the milk, the saliva, the bile, the urine, &c. 

266. At first glance there would seem to be nothing in 
common between the organs which secrete the tears and 
that which produces the bile, or between the kidneys and 
the salivary glands. Still they all have the same element- 
ary structure. Every gland is composed of minute vesi- 
cles, or extremely thin membranous sacs, generally too 
small to be discerned by the naked eye, but easily distin- 
guished by the microscope. Sometimes these vesicles are 

single and open sepa- 
rately at the surface ; 
they are then called 
crypts or follicles, 
but more frequently 
they unite to form 
Fig. 93. clusters opening into a 

common canal, which itself unites with 

the canals of similar clusters to form 

trunks of various sizes, such as are 

found in the salivary glands (Fig. 92), 

in the mamma?, or in the liver, which is 

merely a very large gland receiving a 

large quantity of blood from the veins 

of the alimentary canal. Fig. 94. 

267. Sometimes the canals of the little clusters do not 
unite, but open separately upon the surface of the body or 
into its cavities, as in the intestinal glands or those from 
which the perspiration issues (Fig. 94, g). Occasionally, the 
canals themselves combine into bundles composed of a mul- 
titude of parallel tubes, as we find in the kidneys. 

268. The operation of the glands is one of the most ex- 
traordinary and mysterious of the whole organization. By 
virtue of the peculiar properties with which they are en- 


dowed, they select from the blood, which penetrates to their 
remotest ramifications, the elements of the special humors 
they are designed to elaborate. Thus the liver extracts 
the elements of the bile ; the salivary glands the elements 
of saliva ; the pancreas those of the pancreatic juice ; 
and the sudoriferous glands those of the sweat, &c. 

269. Among the humors thus formed by the different 
glands, some are immediately expelled, and the body 
freed from them, as the sweat, the urine, &c. ; these are 
denominated excretions. Others, on the contrary, which 
are properly denominated secretions, are destined either to 
be used as food for the young, as the milk ; or to take part 
in the different functions of the body, as the saliva, the 
tears, the gastric and pancreatic juices, and the bile. The 
last is the most important of all the secretions, and 
hence a liver, or some analogous organ by which bile is 
secreted, is found in animals of every department, whilst 
most of the other glands are only found in certain classes of 

270. In the vertebrates the liver is the largest of the vis- 
cera. It is of a reddish brown color, and varies but little in 
the different classes. In the mollusks it is no less preponde- 
rant. In the gasteropods, like the snails, it envelops the in- 
testine in its folds (Fig. 52) ; and in the acephala, like the 
clam and oyster, it generally surrounds the stomach. In the 
articulated animals it is not so compact, nor so voluminous 
as in the mollusks. In insects it is represented by long 
tubes variously contorted and interlaced (Fig. 51). In the 
Eadiata this organ is largely developed, especially among 
the echinoderms. In the star-fishes it is very large, ex- 
tending into all the recesses of the arms ; and in color and 
structure resembles that of the mollusks. Even in polyps 
we find peculiar brown cells lining the stomach, which 
probably perform functions similar to those of the liver of 
higher animals, 




271. THE functions of vegetative life, of which we have 
treated in the preceding chapters, namely, digestion, circu- 
lation, respiration and secretion, have for their end the pre- 
servation of the individual. We have now to treat of the 
functions that serve for the perpetuation of the species, 
namely those of reproduction (200). 

272. It is a law of nature that animals as well as plants 
are preceded only by individuals of the same species ; and 
vice versa, that none of them can produce a species differ- 
ent from themselves. Reproduction in animals is almost 
universally accomplished by the association of individuals of 
two kinds, males and females, living commonly in pairs or 
flocks, and each of them characterized by peculiarities of 
structure and external appearance. 

273. As this distinction prevails throughout the animal 
kingdom, it is always necessary for obtaining a correct and 
complete idea of a species, to bear in mind the peculiarities 
of both sexes. Every one is familiar with the differences 
between the cock and the hen, the lion and the lioness. 

OF THE EGG. 103 

Among Articulata, the differences are no less striking, the 
male being often of a different shape or color, as in crabs ; 
or having even more complete organs, as in many tribes of 
insects, where the males have wings, while the females are 
deprived of them. 

274. Even higher than specific distinctions are based 
upon peculiarities of the sexes ; for example, the whole 
class of Mammalia is characterized by the fact that the 
female is furnished with organs for nourishing her young 
with a peculiar liquid, the milk, secreted by herself. Again, 
the order Marsupialia, to which the opossum belongs, is dis- 
tinguished by the circumstance of the female having a 
pouch in which the young are received after birth. 

275. That all animals are produced from eggs, (Omne 
vivum ex ovo], is an old adage in Zoology, which modern 
researches have fully confirmed. In tracing back the phases 
of animal life, we invariably arrive at an epoch when the 
incipient animal is enclosed within an egg. It is then called 
an embryo, and the period passed in this condition is called 
the embryonic period. 

276. Before the various classes of the animal kingdom 
had been attentively compared during the embryonic period, 
all animals were divided into two great divisions : the ovi- 
parous, comprising those which lay eggs, such as birds, 
reptiles, insects, mollusks, dec., and the viviparous, which 
bring forth their young alive, namely, the mammalia. 
This distinction lost much of its importance when it was 
shown that viviparous animals are produced from eggs, as 
well as the oviparous ; only that their eggs, instead of being 
laid before the development of the embryo begins, undergo 
their early changes in the body of the mother. Production 
from eggs should therefore be considered as a universal 
characteristic of the Animal Kingdom. 

277. Form of the Egg. The general form of the egg 



Fig. 96. 

Fig. 97. 

is more or less spherical. The eggs of birds have the form 
of an elongated spheroid ; and this form is so constant, that 
the term oval has been universally adopted to designate it. 
But this is by no means the usual form of the eggs in other 

animals. In most instances, on the 
con trary, they are spherical, espe- 
cially among the lower animals. 
Fig. 95. Some have singular appendages, 

as those of the skates and sharks (Fig. 95), which are shaped 
like a hand-barrow, with four hooked horns at the corners. 
The eggs of the hydra, or fresh 
water polyps, are thickly covered 
with prickles (Fig. 96). Those 
of certain insects, for example the 
Podurella, are furnished with fila- 
ments which give them a hairy aspect (Fig. 97) ; others 
are cylindrical or prismatic, and frequently the surface is 

278. Formation of the Egg. The egg originates within 
peculiar organs, namely, the ovaries, which are glands, 
ordinarily situated in the abdominal cavity. So long as they 
remain in the ovary, they are very minute in size. In this 
condition they are called ovarian, or primitive eggs. 
They are nearly the same in all animals, and 
are in fact merely little cells containing yolk- 
substance (?/), including other similar cells, 
namely, the germinative vesicle (g), and the 
germinative dot (rf). The yolk-substance it- 
self is deposited in the ovary, and afterwards 
enclosed in ceils. The number of these eggs is large in 
proportion as the animal stands lower in the class to which it 
belongs. The ovary of a herring contains more than 
25,000 eggs ; whilst that of birds contains a much smaller 
number, perhaps one or two hundred. 

Fig. 98. 

OF THE EGG. 105 

279. Ovulation. Having attained a certain degree of 
maturity, which varies in different classes, the eggs leave 
the ovary. This is called ovulation. It must not be con- 
founded with the laying of the eggs, which is the subsequent 
expulsion of them from the abdominal cavity, either imme- 
diately, or through a particular canal, the oviduct. Ovula- 
tion takes place at certain seasons of the year, and never 
before the animal has reached a particular age, which com- 
monly coincides with its full growth. In a majority of spe- 
cies, ovulation is repeated for a number of years consecu- 
tively, generally in the spring, and frequently several times 
a year. In others, on the contrary, it occurs but once 
during life, at the period of maturity, and the animal 
soon afterwards dies. Thus the butterfly dies shortly after 
having laid her eggs. 

280. The period of ovulation is one of no less interest to 
the zoologist than to the physiologist, since the peculiar 
characteristics of each species are then most clearly 
marked. Ovulation is to animals what flowering is to 
plants ; and indeed, few phenomena are more interesting to 
the student of nature than those exhibited by animals at the 
pairing season. Then their physiognomy is the most 
animated, their song the most melodious, and their attire the 
most brilliant. Some birds appear so different at this time, 
that zoologists are always careful to indicate whether or not 
a bird is represented at the breeding season. Similar differ- 
ences occur also among fishes and other animals, whose 
colors are then much brighter. 

281. Laying. After leaving the ovary, the eggs are 
either discharged from the animal, that is, laid ; or they 
continue their development within the parent animal, as is 
the case in some fishes and reptiles, which for that reason 
have been named ovo -viviparous animals. The eggs of the 
mammalia are not only developed within the mother, but 


become intimately united to her ; this peculiar mode of de- 
velopment has received the name of gestation. 

282. Eggs are sometimes laid one by one, as in birds ; 
sometimes collectively and in great numbers, as in the 
frogs, the fishes, and most of the invertebrates. In 
some instances they are united in clusters by a 
gelatinous envelop ; or are enclosed in cases or be- 
tween membranous discs, forming long strings, as in 
the eggs of the Pyrula (Fig. 99). The conditions 

FigToi. under which the eggs of different animals are 
placed, on being laid, are very different. The 
eggs of birds, and of some insects, are deposited 
in nests constructed for that purpose by the 
parent. Other animals carry their eggs at- 
tached to their bodies ; sometimes under the 
tail, as in the lobsters and crabs, sometimes 
hanging in large bundles on both sides of the 
tail, as in the Monoculus (Fig. 100, a). 

283. Some toads carry them on the back, Fig. 100. 
and, what is most extraordinary, it is the male which under- 
takes this office. Many mollusks, the Unio for example, have 
them attached to the gills during incubation. In the polyps 
they hang in clusters (Fig. 77, o), either inside or outside, at 
the bottom of the cavity of the body. Some insects, such as 
the gad-flies, deposit their eggs on other animals. Finally, 
many abandon their eggs to the elements, taking no fur- 
ther care of them after they have been laid ; such is the 
case with most fishes, some insects, and many mol- 
lusks. As a general rule, it may be said that animals take 
the more care of their eggs and brood, as they occupy a 
higher rank in their proper class. 

284. The development of the embryo does not always take 
place immediately after the egg is laid. A considerable 
time even may elapse before it commences. Thus, the first 

OF THE EGG. 107 

eggs laid by the hen do not begin to develop until the whole 
number which is to constitute the brood is deposited. The 
eggs of the butterfly and of most insects are laid in autumn, 
and remain in the same condition until the following spring. 
Daring this time the principle of life in the egg is not 
extinct, but is simply inactive, or in a latent state. This 
tenacity of life is displayed in a still more striking man- 
ner in plants. The seeds, which are equivalent to eggs, 
preserve for years, and even for ages, their power to germi- 
nate. Thus, wheat taken from the catacombs of Egypt 
has been made to sprout and grow in some well-authenti- 
cated cases. 

285. A certain degree of warmth is requisite for the 
hatching of eggs. Those of birds, especially, demand a uni- 
form temperature, corresponding to the natural heat of the 
future bird, to be constantly applied for a certain length of 
time ; this is naturally supplied by the body of the parent. 
In other words, incubation is necessary for their growth. 
Incubation is not a purely vital phenomenon, but may be 
readily imitated by artificial means. Some birds of warm 
climates dispense with this task ; for example, the ostrich 
often contents herself with depositing her eggs in the sand 
of the desert, where they are hatched of themselves. In 
like manner, the eggs of most birds may be hatched at will, 
by maintaining them at the proper temperature. Before en- 
tering into the details of embryonic transformations, a few 
words are necessary respecting the composition of the egg. 

286. Composition of the Egg. The egg is composed 
of several substances, varying in structure, as well as in 
appearance. Thus, in a a new laid hen's egg (Fig. 101), 
we have first a calcareous shell ; then an albuminous sub- 
stance, the wldie ; within this the yolk ; and before it was 
laid, there was in the midst of the latter a minute vesicle, 
the germinative vesicle (Fig. 99, ^), containing a still smaller 


one, the germinative dot (d). These different parts are 

not equally important in a physio- 
logical point of view. The most 
conspicuous of them, namely, the 
shell and the white, are not essential 
parts, and therefore are often want- 
ing ; while the yolk, the germinative 
Fig. 101. vesicle, and the germinative dot are 

found in the eggs of all animals, and out of these, and 

these only, the germ is formed, in the position shown by 

Fig. 101, e. 

287. The vitellus or yolk (Fig. 101, y) is the most essential 
part of the egg. It is a liquid of variable consistence, some- 
times opaque, as in the egg of birds, sometimes transparent 
and colorless, as in the eggs of some fishes and mollusks. 
On examination under the microscope, it appears to be com- 
posed of an accumulation of granules. The yolk is sur- 
rounded by a very thin skin, the vitelline membrane (Fig. 
98, v). In some insects, when the albumen is wanting, this 
membrane forms the exterior covering of the egg ; in such 
cases it is generally of a firm consistence, and sometimes 
even horny. 

288. The germinative vesicle (Fig. 98, g) is a cell of ex- 
treme delicacy, situated, in the fresh egg, near the middle of 
the yolk, and easily recognized by the greater transparency 
of its contents when the yolk is opaque, as in the hen's egg, 
or by its outline, when the yolk itself is transparent, as in the 
fish. It contains one or more little spots, somewhat opaque, 
appearing as small dots, the germinal dots (rf). On closer 
examination these dots are themselves found to contain 
smaller nucleoli. 

289. The albumen, or white of the egg, (Fig. 101, a), is a 
viscous substance, generally colorless, but becoming white on 
coagulation. Voluminous as it is in bird's eggs, it neverthe- 


less plays but a secondary part in the history of their devel- 
opment. It is not formed in the ovary, like the yolk, but is 
secreted by the oviduct, and deposited around the yolk 
during the passage of the egg through that canal. It con- 
sists of several layers, one of which, the chalaza (c), is 
twisted. On this account, the eggs of those animals in 
which the oviduct is wanting are generally without the albu- 
men. Like the yolk, the albumen is surrounded by a single 
or double membrane, the shell membrane, which, in birds 
and some reptiles and mollusks, is again protected by a cal- 
careous covering, forming a true shell (s). In most cases, 
however, this envelop continues membranous, particularly in 
the eggs of the mollusks, most crustaceans and fishes, sala- 
manders, frogs, &c. Sometimes it is horny, as in the sharks 
and skates. 



290. The formation and development of the young animal 
within the egg is a most mysterious phenomenon. From a 
hen's egg, for example, surrounded by a shell and com- 
posed, as we have seen (Fig. 101), of the albumen and the 
yolk, with a little vesicle in the middle, there is produced, at 
the end of a certain time, a living animal, composed in part 
of totally different elements ; endowed with organs perfectly 
adapted to the exercise of all the functions of animal and 
vegetative life, having a pulsating heart, intestines fitted for 
digestion, organs of sense for the reception of outward im- 
pressions, and having, moreover, the faculty of performing 
voluntary motions, and of experiencing pain and pleasure. 



To learn how this takes place is certainly sufficient to excite 
the curiosity of every intelligent person. 

291. By opening eggs which have been subjected to incu- 
bation for different periods of time, we may easily satisfy 
ourselves that these changes are effected gradually. We 
thus find that those which have undergone but a short 
incubation exhibit only faint indications of the future ani- 
mal ; while those which have been sat upon for a longer 
period include an embryo chicken proportionally more de- 
veloped. Modern researches have taught us that these 
gradual changes, although complicated, and at first sight so 
mysterious, follow laws which are uniformly the same in 
each department of the Animal Kingdom. 

292. The study of these changes constitutes that peculiar 
branch of Physiology called EMBRYOLOGY ; and as there are 
distinctions of the four great departments of the Animal 
Kingdom perceptible at an early stage of embryonic 
life, quite as positive as those found at maturity ; as also, 
the phases of embryonic development indicate still other 
grounds for natural classification, we propose to give the 
outlines of Embryology, so far as it is concerned in zoologi- 
cal arrangement. 

293. In order to understand the successive steps of em- 
bryonic development, we must bear in mind that the whole 
animal body is composed of tissues, whose elements are 
cells (39). These cells are much diversified in the full 
grown animal ; but, at the commencement of embryonic 
life, the whole embryo is composed of minute cells of nearly 
the same form and consistence. These cells originate 
within the yolk, and constantly undergo new changes under 
the influence of life. New cells are formed, while others 
disappear, or are modified so as to become blood, bones, 
muscles, nerves, &c. 

294. We may form some idea of this singular process, by 
noticing how, in the healing of a wound, new substance 


and a new skin is supplied by the transformations of the 
blood. Similar changes take place in the embryo, during 
its early life ; only, instead of being limited to a part of 
the body, they pervade the whole animal. 

295. The series of changes commences, in most animals, 
soon after the eggs are laid ; in others, the birds for 
example, they are delayed till the commencement of 
incubation. The yolk, which before was a mass of uni- 
form appearance, now begins to present a diversified 
aspect. Some portions become more opaque, and others 
more transparent ; and the germinal vesicle, which was 
in the midst of the yolk, is seen at the upper part of it, 
where the germ is to be formed. These early changes 
are accompanied, in some animals, by a rotation of the 
yolk inside of the egg, as may be distinctly seen in the 
eggs of some of the mollusks, especially of the snails. 

296. At the same time the yolk divides itself into two 
spheres, which are again regularly subdivided into two more, 
and so on, till the whole yolk assumes the form of a mulberry, 
each of the spheres composing the mulberry having in its inte- 
rior a transparent vesicle. In many animals, however, these 
divisions or fissures are only temporary, and seem to be mere- 
ly a peculiar mode of transformation common to all inverte- 
brate animals, and also to fishes, naked reptiles, and mam- 
mals, but not yet observed in birds and the higher reptiles.* 

297. In the next place, there appears upon the yolk of 
the Vertebrates a disc-shaped protuberance, composed of 
little cells, which has been variously designated under 
the names of germinative disc, proligerous disc, blasto- 
derma, germinal membrane, or simply the germ. This 
disc gradually extends itself, until it embraces the whole, 
or nearly the whole, of the yolk. 

* In the Birds and higher reptiles we find, instead, a peculiar organ called 
cicatricula, which may, nevertheless, have been formed by a similar pro- 
cess before the egg was laid. 



298. At this early epoch, namely, a few days, and, in 

some animals, a 
few hours after 
development has 
begun, the germ 
Fig. 102. Fig. 103. consists of a sin- 

gle layer composed of very minute cells, all of them having 
the same appearance and the same form (Fig. 102, g). But 
soon after, as the germ increases in thickness, several layers 
may be discerned (Fig. 103), which become more and 
more distinct. 

299. The upper layer (s), in which are subsequently 
formed the organs of animal life, namely, the nervous 
system, the muscles, the skeleton, &c. (59), has received 
the name of serous or nervous layer. The lower layer (in], 
which gives origin to the organs of vegetative life, and 
especially to the intestines, is called the mucous or vegeta- 
tive layer, and is generally composed of larger cells than 
those of the upper or serous layer. Finally, in the em- 
bryos of vertebrated animals, there is a third layer (v), 
interposed between the two others, and giving rise to the 
organs of circulation and to the blood ; whence it has 
been called blood layer, or vascular layer. 

300. Even before this epoch, we can generally distin- 
guish, from the manner in which the germ is modified, to 
what department of the animal kingdom the individual is to 
belong. Thus in the Articulata, the germ is divided into 

segments, indicating the rings of the 
body, as for example, in the embryo 
of the crabs (Fig. 104). The germ 
of the vertebrated animals, on the 
other hand, displays a longitudinal 
Fig. 104. Fig. 105. furrow, which marks the position 
the future back-bone is to occupy (Fig. 105). 


301. The development of this furrow is highly impor- 
tant in indicating the plan of structure of vertebrated ani- 
mals in general, as will be shown by the following figures, 
which represent vertical sections of the embryo at different 
epochs.* At first the furrow (Fig. 106, I), is very shal- 

Fig. 106. 

Fig. 107. 

Fig. 103. 

low, and a little transparent narrow band appears under 
it, called the primitive stripe (a). The walls of the 
furrow consist of two raised edges formed by a swel- 
ling of the germ along both sides of the primitive stripe. 
Gradually, these walls grow higher, and we perceive that 
their summits have a tendency to approach each other, as 
seen in Fig. 107 ; at last they meet and unite completely, 
so that the furrow is now changed into a closed canal (Fig. 
108, Z>). This canal is soon filled with a peculiar liquid 
from which the spinal marrow and brain are to be formed. 
302. The primitive stripe is gradually obliterated by a 
peculiar organ of a cartilaginous nature, the dorsal cord, 
formed in the lower wall of the dorsal canal. This is 
found in the embryos of all vertebrates, and is the represent- 
ative of the back-bone. In the mean time, the margin of 
the germ gradually extends farther and farther over the 
yolk, so as finally to enclose it entirely, and form another 
cavity in which the organs of vegetative life are to be 
developed. Thus the embryo of vertebrates has two cavi- 
ties, namely, a superior, very small one, for the nervous sys- 
tem, and an inferior, much larger one, for the intestines. 

* Only the cut edge of the embryo is supposed to be seen, whereas, if 
viewed from above, it would be seen to extend over the yolk in every direc- 
tion ; so that the furrow at b, of Fig. 106, would be seen as iu Fig. 105. 



303. In all classes of the Animal Kingdom, the embryo 

rests upon the yolk, and covers it like a 
cap. But the direction by which its edges 
approach each other, and unite to form the 
cavity of the body, is very unlike in differ- 
ent animals ; and these several modes 
are of high importance in classification. 
Fi?. 109. Among the Vertebrates, the embryo lies 
with its face or ventral surface towards the yolk (Fig. 109), 
and thus the suture, or line at which the edges of the germ 
unite to enclose the yolk, and which in the mammals forms 
the navel, is found at the belly. Another suture is found 
along the back, arising from the actual folding upwards of 
the upper surface of the germ, to form the dorsal cavity. 

304. The embryo in the Articulata, on the contrary, lies 
with its back upon the yolk, as seen in the following figure, 
which represents an embryo of Podurella ; 
consequently the yolk enters the body from 

the opposite direction ; and the suture, 
which in the vertebrates is found on the 
belly, is here found on the back. In the 
Mollusks there is this peculiarity, that the 
whole yolk is changed into the substance Fig. no. 
of the embryo ; whilst in Vertebrates, a part of it is re- 
served, till a later period, to be used as food by the embryo. 
Among Radiata the germ is formed around the yolk, and 
seems to surround the whole of it, from the first. 

305. Among the vertebrated animals, the development of 
the embryo may be best observed in the eggs of fishes. 
Being transparent, they do not require to be cut open, and, 
by sufficient caution, we may observe the whole series of 
changes upon the same individual, and thus make sure of 
the succession in which the organs appear ; whereas, if we 
employ the eggs of birds, which are opaque, we are obliged 
to sacrifice an egg for each observation. 


306. To illustrate these general views as to the develop- 
ment of the embryo, we will briefly describe the principal 
phases, as they have been observed in the White-fish of 
Europe, which belongs to the salmon family. The follow- 
ing magnified figures will illustrate this development, and 
show the successive appearance of the different organs. 

Fig. 111. 

Fig. 112. 

Fig. 113. 

307. The egg when laid (Fig. Ill) is spherical, about 
the size of a small pea, and nearly transparent. It has no 
albumen, and the shell-membrane is so closely attached to 
the membrane of the yolk, that they cannot be distinguished. 
Oil-like globules are scattered through the mass of the yolk, 
or grouped into a sort of disc, under which lies the germina- 
tive vesicle. The first change in such an egg occurs a few 
hours after it has been laid, when the shell-membrane 
separates from the yolk-membrane, in consequence of the 
absorption of a quantity of water (Fig. 112). Between the 
shell-membrane (sm), and the yolk (?/), there is now a con- 
siderable transparent space, which corresponds, in some 
respects, to the albumen found in the eggs of birds. 

308. Soon afterwards we see, in the midst of the oil-like 

Fig. 114. 

Fig. 115. 

Fig. 110. 

globules, a swelling in the shape of a transparent vesi- 
cle (Fig. 113, g), composed of very delicate cells. This is 
the first indication of the germ. This swelling rapidly en- 
larges until it envelops a large part of the yolk, when a 



depression is formed in it (Fig. 114). This depression 
becomes by degrees a deep furrow, and soon after a second 
furrow appears at right angles with the former, so that the 
germ now presents four elevations (Fig. 115). The subdi- 
vision goes on in this way, during the second and third 
days, until the germ is divided into numerous little spheres, 
giving it the appearance of a mulberry (Fig. 116). This 
appearance, however, does not long continue ; at the end of 
the third day, the fissures again disappear and leave no 
visible traces. After this, the germ continues to extend 
as an envelop around the yolk, which it at last entirely 

309. On the tenth day, the first outlines of the embryo 
begin to appear, and we soon distinguish in it a depression 
between two little ridges, whose edges are constantly ap- 
proaching each other until they unite and form a canal (Fig. 
117, ft), as has been before shown. At the same time 

Fig. 117. 

Ficr. 118. 

Fig. 119. 

an enlargement of one of the extremities is observed. 
This is the rudiment of the head (Fig. 118), in which 
may soon be distinguished traces of the three divisions 
of the brain (Fig. 119), corresponding to the senses of 
sight (/?i), hearing (e), and smell (jo). 

310. Towards the thirteenth day we see, in the place af- 
terwards occupied by the back-bone, a transparent, cartilag- 
inous cord, composed of large cells, on which transverse 
divisions are successively forming (Figs. 120, 121, c). This 
is the dorsal cord, an organ which, as we have before seen, 


is common to all embryos of vertebrated animals. It 
always precedes the formation of the back-bone ; and in 
some fishes, as the sturgeon, this cartilaginous or embry- 
onic state is permanent through life, and no true back-bone 
is ever formed. Soon after, the first rudiments of the eye 
appear, being a fold in the external membrane of the 
germ, in which the crystalline lens (Fig. 121, #) is after- 
wards formed. At the same time we see at the posterior 
part of the head an elliptical vesicle, which is the rudiment 
of the ear. 

311. After the seventeenth day, the mucous layer divides 
into two sheets, the inferior of which becomes the intestine. 
The heart shows itself about the same time, under the form 
of a simple cavity (Fig. 121, /?), in the midst of a mass 
of cells belonging to the middle or vascular layer. As 
soon as the cavity of the heart is closed in, regular motions 
of contraction and expansion are perceived, and the glo- 
bules of blood are seen to rise and fall in conformity with 
these motions. 

312. There is as yet, however, no circulation. It is not 
until the thirtieth day that its first traces are manifest 
in the existence of two currents, one running towards the 
head, the other towards the trunk (Fig. 122), with sim- 


Fisr. 120. 

Fisr. 121. 

Fig. 122. 

ilar returning currents. At this time the liver begins 
to form. Meanwhile the embryo gradually disengages itself, 
at both extremities, from its adherence to the yolk ; the tail 


becomes free, and the young animal moves it in violent 

313. The embryo, although still enclosed in the egg, now 
unites all the essential conditions for the exercise of the 
functions of animal life. It has a brain, an intestine, 
a pulsating heart and circulating blood, and it moves 
its tail spontaneously. But the forms of the organs are 
not yet complete ; nor have they yet acquired the pre- 
cise shape that characterizes the class, the family, the 
genus and the species. The young White-fish is as yet 
only a vertebrate animal in general, and except for 
the fin that surrounds its body, might be taken for the 
embryo of a frog. 

314. Towards the close of the embryonic period, after the 
fortieth day, the embryo acquires a more proper shape. 
The head is more completely separated from the yolk, 
the jaws protrude, and the nostrils approach nearer and 
nearer to the end of the snout ; divisions are formed in 
the fin which surrounds the body ; the anterior extremities, 
which were indicated only by a small protuberance, assume 
the shape of fins ; and finally, the openings of the gills 
appear, one after the other, so that we cannot now fail to 
recognize the type of fishes. 

315. In this state, the young white-fish escapes from the 

egg, about the sixtieth 
day after it is laid (Fig. 
123). But its develop- 
ment is still incom- 
Fig. 123. plete. The outlines are 

yet too indistinct for us to recognize the genus and the 
species to which the fish belongs ; at most we distinguish 
its order only. The opercula or gill-covers are not 
formed ; the teeth are wanting ; the fins have as yet no rays ; 
the mouth is underneath, and it is some time before it as- 


sumes its final position at the most projecting point of the 
head. The yolk is suspended from the belly, in the form of 
a large bladder, but it daily diminishes in size, until it is 
at length completely taken into the animal. The duration 
of these metamorphoses varies extremely in different fishes ; 
some accomplish it in the course of a few days, while in 
others months are required. 

315 a. In frogs and all the naked reptiles, the development is very 
similar to that of fishes. It is somewhat different in the scaly rep- 
tiles (snakes, lizards and turtles), which have peculiar membranes 
surrounding and protecting the embryo during its growth. From one 
of these envelops, the allanto'is (Fig. 125, a,) is derived their common 
name of Allan to'idian Vertebrates, in opposition to the naked reptiles and 
fishes, which are called Anallanto'idian. 

315 6. The Allantoidian Vertebrates differ among themselves in several 
essential peculiarities. Among Birds, as well as in the scaly reptiles, we 
find at a certain epoch, when the embryo is already disengaging itself from 
the yolk, a fold rising around the body from the upper layer of the germ, 
so as to present, in a longitudinal section, two prominent walls (Fig. 124, 

Fig. 124. Fig. 125. 

xx). These walls, converging from all sides upwards, rise gradually 
till they unite above the middle of the back (Fig. 125). When the 
junction is effected, which in the hen's egg takes place in the course 
of the fourth day, a cavity is formed between the back of the embryo 
(Fig. 126, e) and the new membrane, whose walls are called the am- 
nios. This cavity becomes filled with a peculiar liquid, the amniotic 

315 c. Soon after the embryo becomes enclosed in the amnios, a 
shallow pouch forms from the mucous layer below the posterior ex- 
tremity of the embryo, between the tail and the vitelline mass. This 
pouch, at first a simple little sinus (Fig. 125, a), grows larger and larger, 
till it forms an extensive sac, bending backwards and upwards, so as to 



316. As a general fact, it should be further stated, that 
the envelops which protect the egg, and also the embryo, 
are the more numerous and complicated as animals be- 
long to a higher class, and produce a smaller number of 
eggs. This is particularly evident when contrasting the in- 
numerable eggs of fishes, discharged almost without protec- 
tion into the water, with the well-protected eggs of birds, and 
still more with the growth of young mammals within the 
body of the mother. 

separate completely the two plates of the amnios (Fig. 126, a), and finally 

Fig. 126. 

to enclose the embryo, with the amnios, in another large sac. The tuhular 
part of this sac, which is nearest the embryo, is at last transformed into 
the urinary bladder. The heart (h) is already very large, with minute 
arterial threads passing off from it. 

315 d. The development of mammals exhibits the following peculiari- 
ties. The egg is exceedingly minute, almost microscopical, although com- 
posed of the same essential elements as those of the lower animals 
The vitelline membrane, called chorion, in this class of animals, is 
comparatively thicker (Fig. 127, v,) always soft, surrounded by peculiar 

cells, being a kind of albumen. 
The chorion soon grows proportion- 
ally larger than the vitelline sphere 
itself (Fig. 123, y), so as no longer to 
invest it directly, being separated 
from it by an empty space (&). The 
germ is formed in the same position 
Fig. 127. Fig. 128. as in the other classes of Vertebrates, 

namely, at the top of the vitellus (Fig. 129) ; and here also two layers 
may be distinguished, the upper or serous layer (s), and the lower or 


317. But neither in fishes, nor in reptiles, nor in birds, 
does the vitelline membrane, or any other envelop of the egg, 
take any part in the growth of the embryo ; while on the 
contrary, in the mammals, the chorion, which corresponds 
to the vitelline membrane, is vivified, and finally becomes 
attached to the maternal body, thus establishing a direct 
connection between the young and the mother ; a connec- 
tion which is again renewed in another mode, after birth, 
by the process of nursing her milk. 

mucous layer (m). As it gradually enlarges, the surface of the cho- 
rion becomes covered 
with little fringes, which, 
at a later epoch, will 
be attached to the mother 
by means of similar 
fringes arising from the 
walls of the matrix, or 
organ which contains the 
embryo. Fig. 129. Fig. 130. 

315 e. The embryo itself undergoes, within the chorion, changes similar 
to those described in the birds ; its body and its organs are formed in the 
same way; an amnios encloses it, and an allantois grows out of the lower 
extremity of the little animal. As soon as the allantois has surrounded 
the embryo, its blood vessels become more and more numerous, so as to 

extend into the fringes of the chorion (Fig. 131, 
pe), while, on the other hand, similar vessels 
from the mother extend into the corresponding 
fringes of the matrix (pm), but without directly 
communicating with those of the chorion. These 
two sorts of fringes soon become interwoven so 
as to form an intricate organ filled with blood, 
called the placenta, to which the embryo remains 
p. . . suspended until birth. 

315 f. From the fact above stated, it is clear that there are three modifi- 
cations of embryonic development among vertebrated animals, namely, 
that of fishes and naked reptiles, that of scaly reptiles and birds, and that 
of the mammals, which display a gradation of more and more complicated 
adaptation. In fishes and the naked reptiles, the germ simply encloses 
the yolk, and the embryo rises and grows from its upper part. In the 
scaly reptiles and birds there is besides, an amnios arising from the peri- 
pheric part of the embryo, and an allantois growing out of the lower cavity, 
both enclosing and protecting the germ. 





318. As a general result of the observations which have 
been made, up to this time, on the embryology of the vari- 
ous classes of the Animal Kingdom, especially of the verte- 
brates, it may be said, that the organs of the body are succes- 
sively formed in the order of their organic importance, 
the most essential being always the earliest to appear. In 
consequence of this law, the organs of vegetative life, the 
intestines and their appurtenances, make their appearance 
subsequently to those of animal life, such as the nervous 
system, the skeleton, &c. ; and these, in turn, are pre- 
ceded by the more general phenomena belonging to the 
animal as such. 

319. Thus we have seen that, in the fish, the first changes 
relate to the formation and furrowing of the germ, W 7 hich is 
a character common to all classes of animals. It is not un- 
til a subsequent period that we trace the dorsal groove, 
which indicates that the forming animal will have a 
double cavity, and consequently belong to the division of 
the vertebrates ; an indication afterwards fully confirmed 
by the successive appearance of the brain and the organs of 
sense. Later still, the intestine is formed, the limbs 
become evident, and the organs of respiration acquire 
their definite form, thus enabling us to distinguish with 
certainty the class to which the animal belongs. Finally, 
after the egg is hatched, the peculiarities of the teeth, 
and the shape of the extremities mark the genus and 

320. Hence, the embryos of different animals resem- 


ble each other more strongly in proportion as we examine 
them at an earlier period. We have already stated that, 
during almost the whole period of embryonic life, the young 
fish and the young frog scarcely differ at all : so it is also 
with the young snake compared with the embryo bird. The 
embryo of the crab, again, is scarcely to be distinguished 
from that of the insect ; and if we go still farther back in 
the history of development, we come to a period when no 
appreciable difference whatever is to be discovered between 
the embryos of the various departments. The embryo of the 
snail, when the germ begins to show itself, is nearly the 
same as that of a fish or a crab. All that can be predicted 
at this period is, that the germ which is unfolding itself 
will become an animal ; the class and the group are not yet 

321. After this account of the history of the develop- 
ment of the egg, the importance of Embryology to the 
study of Zoology cannot be questioned. For evidently, if 
the formation of the organs in the embryo takes place in an 
order corresponding to their importance, this succession 
must of itself furnish a criterion of their relative value 
in classification. Thus, those peculiarities that first ap- 
pear should be considered of higher value than those 
that appear later. In this respect, the division of the Ani- 
mal Kingdom into four types, the Vertebrates, the Articu- 
lates x the Mollusks, and the Radiates, corresponds perfectly 
with the gradations displayed by Embryology. 

322. This classification, as has been already shown (61), 
is founded essentially on the organs of animal life, the 
nervous system and the parts belonging thereto, as found in 
the perfect animal. Now, it results from the above account, 
that in most animals the organs of animal life are precisely 
those that are earliest formed in the embryo ; whereas those 
of vegetative life, on which is founded the division into 


classes, orders, and families, such as the heart, the respiratory 
apparatus, and the jaws, are not distinctly formed until after- 
wards. Therefore a classification, to be true and natural, 
must accord with the succession of organs in the embryonic 
development. This coincidence, while it corroborates the 
anatomical principles of Cuvier's classification of the Ani- 
mal Kingdom, furnishes us with a new proof that there 
is a general plan displayed in every kind of development. 

323. Combining these two points of view, that of Embry- 
ology and that of Anatomy, the four divisions of the Animal 
Kingdom may be represented by the four figures which 
are to be found, at the centre of the diagram, at the be- 
ginning of the volume. 

324. The type of Vertebrates, having two cavities, one 
above the other, the former destined to receive the nervous 
system, and the latter, which is of a larger size, for the 
intestines, is represented by a double crescent united at the 
centre, and closing above, as well as below. 

325. The type of Articulata, having but one cavity, and 
growing from below upwards, (the nervous system forming 
a series of ganglions, placed below the intestine,) is repre- 
sented by a single crescent, with the horns directed up- 

326. The type of Mollusks having also but one cavity, the 
nervous system being a simple ring around the oesophagus, 
with threads going off from it, is represented by a single 
crescent with the horns turned down. 

327. Finally, the type of Radiata, the radiating form of 
which is seen even in the youngest individuals, is repre- 
sented by a star. 




328. WE have shown in the preceding chapter, that 
ovulation, or the development of the embryo from the 
egg, is common to all classes of animals, and must be 
considered as the great law for the reproduction of species. 
Two other modes of reproduction, applying to only a limited 
number of animals, remain to be mentioned, namely, gem- 
miparous reproduction, or multiplication by means of buds, 
and fissiparous reproduction, or propagation by division ; 
and also some still more extraordinary modifications yet in- 
volved in much obscurity. 

329. Reproduction ~by buds occurs among the polyps and 
some of the infusoria. On the stalk, or even 

on the body of the Hydra, and of many Infu- 
soria (Fig. 132), there are' formed buds, like 
those of plants. On close examination they 
are found to contain young animals, at first 
very imperfectly formed, and communicating 
at the base with the parent body, from which 
they derive their nourishment. By degrees the pig. 132. 
animal is developed ; in most cases, the tube by which it is 




attached to the parent withers away, the animal is detached 
and becomes independent. Others remain through life 
attached to the parent stalk, and in this respect, present 
a more striking analogy to the buds of plants. But in 
the polyps, as in trees, budding is only an accessary mode 
of reproduction, which presupposes a trunk already existing, 
originally the product of ovulation. 

330. Reproduction by division, or fissiparous reproduction, 
is still more extraordinary ; it takes place only in polyps and 
some infusoria. A cleft or fission at some part of the body 
takes place, very slight at first, but constantly increasing in 

depth, so as to become a deep 
furrow, in the same way as 
takes place in the yolk, at the 
beginning of embryonic devel- 
opment ; at the same time the 
organs are divided and be- 
come double, and thus two in- 
dividuals are formed of one, so similar to each other that 
it is impossible to say which is the parent and which the 
offspring. The division takes place sometimes vertically, 
as for example, in the Vorticella (Fig. 133) and in some 

Fi?. 133. 

Fig. 134. 

Polyps (Fig. 134), and sometimes transversely. In some 
Infusoria, the Paramecia, for instance, this division occurs 
as often as three or four times in a day. 

331. In consequence of the same faculty, many animals 
are able to reproduce various parts of their bodies when 
accidentally lost. It is well known that crabs and spi- 
ders, on losing a limb, acquire a new one. The same 


happens with the arms of the star-fishes. The tail of a 
lizard is also readily reproduced. Salamanders even pos- 
sess the faculty of reproducing parts of the head, including 
the eye with all its complicated structure. Something simi- 
lar takes place in our own bodies, when a new skin is 
formed over a wound, or when a broken bone is reunited. 

332. In some of the lower animals, this power of repara- 
tion is carried much farther, and applies to the whole body, 
so as closely to imitate fissiparous reproduction. If an 
earth-worm be divided into several pieces, the injury is 
soon repaired ; and if we cut in fragments a fresh-water 
polyp, each one speedily becomes a perfect animal. Some- 
thing like this reparative faculty is seen in the vegetable 
kingdom, as well as the animal. A willow branch, planted 
in a moist soil, throws out roots below and branches above ; 
and thus, after a time, assumes the shape of a perfect tree. 

333. These various modes of reproduction do not exclude 
each other. All animals which propagate by gemmipa- 
rous or fissiparous reproduction also lay eggs. Thus the 
fresh-water polyps (Hydra) propagate both by eggs and by 
buds. In Vorticella, according to Ehrenberg, all three 
modes are found ; it is propagated by eggs, by buds, 
and by division. Ovulation, however, is the mode of re- 
production that most generally prevails ; the others, and 
also alternate reproduction, are additional means employed 
by nature to secure the perpetuation of the species. 



334. It is a matter of common observation, that individu- 
als of the same species have the same general appear- 


ance, by which their peculiar organization is indicated. 
The transmission of these characteristics, from one gene- 
ration to the next, is justly considered as one of the great 
laws of the Animal and Vegetable Kingdoms. It is indeed 
one of the points on which the definition of species is 

335. But it does not follow that animals must resemble 
their parents in every condition, and at every epoch of their 
existence. On the contrary, as we have seen, this resem- 
blance is very faint in most species, at birth, and some of 
them, such as the butterfly and the frog, undergo complete 
metamorphoses, before attaining their final shape. Never- 
theless, we do not hesitate to refer the tadpole and the frog 
to the same species ; and so with the caterpillar and the 
butterfly, because we know that it is the same individual 
observed in different stages of development. 

336. There is also another series of cases in which the 
offspring not only do not resemble the parent at birth, but 
moreover remain different during their whole life, so that 
their relationship is not apparent until a succeeding genera- 
tion. The son resembles not the father, but the grand- 
father ; and in some cases the resemblance reappears only 
at the fourth or fifth generation, and even later. This sin- 
gular mode of propagation has received the name of alter- 
nate reproduction. The phenomena attending it have been 
of late the object of numerous scientific researches, which 
are the more deserving of our attention, as they furnish a 
solution to several problems alike interesting in a zoological 
and in a philosophical point of view. 

337. Alternate reproduction was first observed among 
the Salpse. These are marine mollusks, without shells, be- 
longing to the family Tunicata. They are distinguished 
by the curious peculiarity of being united together in 
considerable numbers, the mouth (m) being free, so as to 



form long chains which float in the sea (Fig. 135). The 

Fig. 136. 

individuals thus joined in floating colonies produce eggs ; 
but in each individual there is generally but one egg formed, 
which is developed in the body of the parent, and from 
which is hatched a little mollusk (Fig. 136), which remains 
solitary, and differs in many respects from the parent. 
This little animal, on the other hand, does not produce 
eggs, but propagates by a kind of budding which gives rise to 
chains seen within the body of the parent (a), and these 
again bring forth solitary individuals, &c. 

338. In some parasitic worms, the alternate reproduction 
is accompanied by still more extraordinary phenomena, as is 
shown by the late discoveries of the Danish naturalist, 
Steenstrup. It is well known that the stagnant pools in 
which fresh- water shells (particularly the Lymnea and the 
Paludina) are found, contain an innumerable variety of 
minute animals of various kinds. Among these is a small 
worm, known to naturalists under the 
name of Cercaria (Fig. 137). When ex- 
amined with a lens, it looks much like 
a tadpole, with a long tail, a triangular 
head, and a large sucker (a) in the mid- 
dle of the body. Various viscera appear 
within, and among others a very distinct 
forked cord (c), which embraces the 
sucker, and which is thought to be the 

Fig. 137. 339. If we watch these worms, which 

always abound in the neighborhood of the shells mentioned , 


we find them after a while attaching themselves, by means 
of their sucker, to the body of the mollusks. When fixed 
they soon undergo considerable alteration. The tail, which 
is now useless, falls off, and the animal surrounds itself 
with a mucous substance, in which it remains nearly motion- 
less, like the caterpillar on its transformation into 
the Pupa. If we remove the little animal from 
its retreat we find it to be no longer a Cercaria, 
but an intestinal worm called Distoma, having 
the shape of Fig. 138, with two suckers. The 
Distoma, therefore, is only a particular state of 
the Cercaria, or rather the Cercaria is only the Fig. iss. 
larva of the Distoma. 

340. What now is the origin of the Cercaria ? The fol- 
lowing are the results of the latest researches on this point. 
At certain periods of the year, we find in the viscera of the 
Lymnea (one of the most common fresh-water mollusks) a 
quantity of little worms of an elongated form, with a well 
marked head, and two posterior projections 
like limbs (Fig. 139). On examining these 
worms attentively under the microscope we 
discover that the cavity of their body is filled 
by a mass of other little worms, which a prac- 
tised eye easily recognizes as young Cercaria, 
Fig. 139. the tail and the other characteristic bifurcated 
organ (a) within it being 
distinctly visible (Fig. 140). 
These little embryos increase //^W?^2^ \, 
in size, distending the worm 
which contains them, and Fig. 140. 

which seemingly has no other office than to protect and 
forward the development of the young Cercaria. It is, as 
it were, their living envelop. On this account, it has been 
called the nurse. 


341. When they have reached a certain size, the young 
Cercarise leave the body of the nurse, and move freely in the 
abdominal cavity of the mollusks, or escape from it into the 
water to fix themselves, in their turn, to the body of another 
mollusk, and begin their transformations anew. 

342. But this is not the end of the series. The nurses of 

the Cercaria are themselves the offspring of little 
worms of yet another kind. At certain seasons, 
we find in the viscera of the Lymnea, worms 
somewhat like the nurses of the Cercaria in 
shape (Fig. 141), but rather longer, more slen- 
der, and having a much more elongated stomach 
(s). These worms contain, in the hinder part 
of the body, little embryos (a), which are the 
Fig. MI. y un g nurses of Figures 139, 140. This gen- 
eration has received the name of grand-nurses. 

343. Supposing these grand-nurses to be the immediate 
offspring of the Distoma (Fig. 138), as is probable, we have 
thus a quadruple series of generation. Four generations 
and one metamorphosis are required to evolve the perfect 
animal ; in other words, the parent finds no resemblance 
to himself in any of his progeny, until he arrives at the 

344. Among the Aphides, or plant-lice, the number of 
generations is still greater. The first generation, which is 
produced from eggs, soon undergoes metamorphoses, and 
then gives birth to a second generation, w T hich is followed 
by a third and so on ; so that it is sometimes the eighth or 
ninth generation before the perfect animal appears as male 
and female, the sexes being then for the first time distinct, 
and the male provided with wings. The female lays eggs 
which are hatched the following year, to repeat the same 
succession. Each generation is an additional step to- 
wards the perfect state ; and as each member of the sue- 


cession is an incomplete animal, we cannot better explain 
their office, than by considering them analogous to the larvae 
of the Cercaria, that is, as nurses.* 

345. The development of the Medusse is not less instruct- 
ive. According to the observations of M. Sars, a Norwegian 
naturalist, the Medusa brings forth living young, which, 
after having burst the covering of the egg, swim about 
freely for some time in the body of the mother. When 
born, these animals have no resemblance whatever to the 
perfect Medusa. They are little cylindrical bodies (Fig. 
142, ), much resembling infusoria, and like them covered 
with fine cilia, by means of which they swim with much 

346. After swimming about freely in the water for some 
days, the little animal fixes itself by one extremity (Fig. 
142, e). At the opposite -extremity a depression is gradu- 

* There is a certain analogy between the larvae of the plant-louse (Aphis) 
and the neuters of the working ants and bees. This analogy has given 
rise to various speculations, and, among others, to the following theory, 
which is not without interest. The end and aim of all alternate gene- 
ration, it is said, is to favor the development of the species in its pro- 
gress towards the perfect state. Among the plant-lice, as among all 
the nurses, this end is accomplished unconsciously, by means of the 
body of the nurse. Now a similar end is accomplished by the working 
ants and bees, only, instead of being performed as an organic function, it is 
turned into an outward activity, which makes them instinctively watch 
over the new generation, and nurse and take care of it. It is no longer the 
body of the nurse, but its instincts, which become the instrument of the 
development. This seems to receive confirmation from the fact that the 
working bees, like the nurses of the plant-lice, are barren females. The at- 
tributes of their sex, in both, seem to consist only in their solicitude for the 
welfare of the new generation, of which they are the natural guardians, 
but not the parents. The task of bringing forth young is confided to other 
individuals, to the queen among the bees, and to the female of the last 
generation among the plant-lice. Thus the barrenness of the working bees, 
which seems an anomaly as long as we consider them complete animals, 
receives a very natural explanation so soon as we look upon them 
merely as nurses. 



ally formed, the four corners (&, f) become elongated, 
and by degrees are transformed into tentacles (c). These 

b chid 


e f g Fig. 142. k 

tentacles rapidly multiply, until the whole of the upper 
margin is covered with them (g). Then transverse 
wrinkles are seen on the body at regular distances, ap- 
pearing first above and extending downwards. These 
wrinkles, which are at first very slight, grow deeper and 
deeper, and at the same time, the edge of each segment 
begins to be serrated, so that the animal presents the ap- 
pearance of a pine cone, surmounted by a tuft of tentacles 
(h) ; whence the name of Strobila, which was originally given 
to it, before it was known to be only a transient state of the 
jelly-fish. The separation constantly goes on, until at last 
the divisions are united by only a very slender axis, and 
resemble a pile of cups placed within each other (i). 
The divisions are now ready for separation ; the upper 
ring first disengages itself, and then the others in succes- 
sion.* Each segment (d) then continues its development by 
itself, until it becomes a complete Medusa (k] ; while, 
according to recent researches, the basis or stalk remains 
and produces a new colony. 

347. It is thus, by a series of metamorphoses, that the 
little animal which, on leaving the egg, has the form of the 

; These free segments have been described as peculiar animals, under 
the name of Ephyra. 



Infusoria, passes in succession through all the phases we have 
described. But the remarkable point in these metamorpho- 
ses is, that what was at first a single individual is thus 
transformed, by tranverse division, into a number of en- 
tirely different animals, which is not the case in ordinary 
metamorphoses. Moreover, the upper segment does not 
accompany the others in their development. Its office seems 
to be accomplished so soon as the other segments begin to 
be independent of it ; being intended merely to favor their 
development, by securing and preparing the substances 
necessary to their growth. In this respect it resembles the 
nurse of the Cercaria. 

348. The Polyps present phenomena no less numerous 
and strange. The Campanularia has a branching, plant- 
like form, with little cup-shaped cells on the ends and in the 
axils of the branches, each of which contains a little animal. 

These cups have not all the same organi- 
zation. Those at the extremity of the 
branches (), and which appear first, are 
furnished with long tentacles, wherewith 
they seize their food (Fig. 143). Those 
in the axils of the branches, and which 
appear late, are females (&), and have no 
such tentacles. Inside of the latter, little 
spherical bodies are found, each having sev- 
143. " era! spots in the middle ; these are the eggs. 
Finally, there is a third form, different from the two preced- 
ing, produced by budding from the female polyp, to which it 
in some sort belongs (c). It is within this third sort that the 
eggs arrive, after having remained some time within the 
female. Their office seems to be to complete the incu- 
bation, for it is always within them that the eggs are 

349. The little animal, on becoming free, has not the 


slightest resemblance to the adult polyp. As in the young 
Medusa, the body is cylindrical, covered with 
delicate cilia. After having remained free for 
some time, the young polyp fixes itself in a flat- 
tened form. By degrees a little swelling rises 
at the centre which elongates, and at last forms 
a stalk. This stalk ramifies, and we soon recog- pj g- 1444 
nize in it the polyp of figure 143, with the three kinds of 
buds, which we may consider as three distinct forms of the 
same animal. 

350. The development of the Campanularia presents, in 
some respects, an analogy with what takes place in the re- 
production of plants, and especially of trees. They should 
be considered as groups of individuals, and not as single 
individuals. The seed, which corresponds to the embryo of 
the Polyp, puts forth a little stalk. This stalk soon ramifies 
by gemmiparous reproduction, that is, by throwing out buds 
which become branches. But ovulation, or reproduction 
by means of seeds, does not take place until an advanced 
period, and requires that the tree should have attained a 
considerable growth. It then produces flowers with pistils 
and stamens, that is, males and females, which are com- 
monly united in one flower, but which in some instances 
are separated, as in the hickories and elders.* 

* Several plants are endowed with organs similar to the third form of 
the Polyps, as we see it in the Campanularia ; for example, the liverwort 
(Marchantiapolymorpha), which has at the base of the cup a little recep- 
tacle, from the bottom of which little disc-like bodies are constantly form- 
ing, which, when detached, send out roots, and gradually become complete 
individuals. Besides that, we find in the Polyps, as in plants, the impor- 
tant peculiarity, that all the individuals are united in a common trunk 
which is attached to the soil ; and that all are intimately dependent on 
each other, so that they perish if severed from the trunk. And if we com- 
pare, in this point of view, the various species in which alternate reproduc- 
tion has been observed, we find that the progress displayed in each type 




351. These various examples of alternate reproduction 
render it evident, that this phenomenon can be no longer 
considered as an anomaly in Nature ; but as the plan for 
advancing those animals in which it occurs to the highest 
point of perfection of which they are susceptible. More- 
over, it has been noticed among all classes of invertebrated 
animals ; while among the Vertebrates it is as yet unknown. 
It would seem that the individual life of the lower animals 
has not force enough to pass continuously, and, as it were, 
with one stride, through all the phases of its development ; 
but, in order to accomplish this, it must either be born in a 
new form, as in the case of alternate reproduction, or un- 
dergo metamorphoses, which are a sort of second birth. 

352. Many analogies may be discovered between alter- 
nate reproduction and metamorphosis. They are parallel 
lines that lead to the same end, namely, the development of 
the species. Nor is it rare to see them coexisting in the 
same animal. Thus, in the Cercaria, we have seen an ani- 
mal produced from a nurse afterwards transformed into a 
Distoma, by undergoing a regular metamorphosis. 

consists precisely in the increasing freedom of the individual in its various 
forms. At first, we have all the generations united in a common trunk, 
as in the lower Polyps and in plants ; then in the Medusa and in some of 
the higher Polyps (the Coryne), the third generation begins to disengage 
itself. Among some of the intestinal worms (the Distoma), the third gen- 
eration is enclosed within its nurse, and this in its turn is contained in the 
body of the grand-nurse, while the complete Distoma lives as a parasitic 
worm in the body of other animals, or even swims freely about in the larva 
state, as Cercaria. Finally, in the Plant-lice, all the generations, the 
nurses as well as the perfect animals, are separate individuals. 


353. In each new generation, as in each new metamor- 
phosis, a real progress is made, and the form which results 
is more perfect than its predecessor. The nurse that pro- 
duces the Cercaria is manifestly an inferior state, just as the 
chrysalis is inferior to the butterfly. 

354. But there is this essential difference between the 
metamorphoses of the caterpillar and alternate reproduction, 
that in the former case, the same individual passes through 
all the phases of development ; whereas, in the latter, the 
individual disappears, and makes way for another, which 
carries out what its predecessors had begun. It would give 
a correct idea of this difference to suppose that the tadpole, 
instead of being itself transformed into a frog, should die, 
having first brought forth young frogs ; or that the chrysalis 
should, in the same way, produce young butterflies. In 
either case, the young would still belong to the same spe- 
cies, but the cycle of development, instead of being accom- 
plished in a single individual, would involve two or more 

355. It follows, therefore, that the general practice of 
deriving the character of a species from the sexual forms 
alone, namely, the male and the female, is not always satis- 
factory ; since there is a large number of animals whose 
various phases are represented by distinct individuals, en- 
dowed with peculiarities of their own. Thus, while in the 
stag the species is represented by two individuals only, stag 
and hind, the Medusa, on the other hand, is represented 
under the form of three different types of animals ; the first 
is free, like the Infusoria, the second is fixed on a stalk, like a 
polyp, and the third again is free, consisting in its turn of 
male and female. In the Distoma also, there are four sepa- 
rate individuals, the grand-nurse, the nurse, the larva or 
Cercaria, and the Distoma, in which the sexes are not sepa- 


rate. Among the Aphides the number is much greater 

356. The study of alternate generation, besides making 
us better acquainted with the organization of animals, 
greatly simplifies our nomenclature. Thus, in future, in- 
stead of enumerating the Distoma and the Cercaria, or the 
Strobila, the Ephyra and the Medusa, as belonging to 
different classes and families, only the name originally given 
to the perfect animal will be retained, and the rest be struck 
from the pages of Zoology, as representing only the transi- 
tory phases of the same species. 

357. Alternate generation always presupposes several 
modes of reproduction, of which the primary is invariably by 
ovulation. Thus, we have seen that the Polyps, the Medusa, 
the Salpa, &c., produce eggs, which are generally hatched 
within the mother. The subsequent generation, on the con- 
trary, is produced in a different manner, as we have shown 
in the preceding paragraphs ; as among the Medusse, by 
transverse division ; among the Polyps and SalpaB, by 
buds, &c. 

358. The subsequent generations are, moreover, not to 
be regarded in the same light as those which first spring 
directly from eggs. In fact, they are rather phases of de- 
velopment, than generations properly so called ; they are 
either without sex, or females whose sex is imperfectly de- 
veloped. The nurses of the Distoma, the Medusa, and the 
Campanularia, are barren, and have none of the attributes 
of maternity, except that of watching over the development 
of species, being themselves incapable of producing young. 

359. Another result of the above observations is this, that 
the differences between animals which are produced by 
alternate generation are less, the earlier the epoch at which 
we examine them. No two animals can be more unlike, 
than an adult Medusa (Fig. 31) and an adult Campanularia 


(Fig. 143) ; they even belong to different classes of the 
Animal Kingdom, the former being an Acaleph, the latter a 
Polyp. On the other hand, if we compare them when first 
hatched from the egg, they appear so much alike that it is 
with the greatest difficulty they can be distinguished. 
They are then little Infusoria, without any very distinct 
shape, and moving with the greatest freedom. The larvse of 
certain intestinal worms, though they belong to a different 
department, have nearly the same form, at one period of 
their life. Farther still, this resemblance extends to plants. 
The spores of certain sea-weeds have nearly the same 
appearance as the young Polyp, or the young Medusa ; and 
what is yet more remarkable, they are also furnished with 
cilia, and move about in a similar manner. But this is only 
a transient state. Like the young Campanularia and the 
young Medusa, the spore of the sea-weed is free for only a 
short time ; soon it becomes fixed, and from that moment 
the resemblance ceases. 

360. Are we to conclude then, from this resemblance of 
the different types of animals at the outset of life, that there 
is no real difference between them ; or that the two King- 
doms, the Animal and the Vegetable, actually blend be- 
cause their germs are similar ? On the contrary, we 
think nothing is better calculated to strengthen the idea of 
the original separation of the various groups, as distinct and 
independent types, than the study of their different phases. 
In fact, a difference so wide as that between the adult 
Medusa and the adult Campanularia must have existed even 
in the young ; only it does not show itself in a manner to be 
appreciable by our senses ; the character by which they sub- 
sequently differ so much, being not yet developed. To 
deny the reality of natural groups, because of these early 
resemblances, would be to take the appearance for the 
reality. It would be the same as saying that the frog and 


the fish are one, because at one stage of embryonic life it is 
impossible, with the means at our command, to distinguish 

36 J. The account we have above given of the develop- 
ment, the metamorphoses and the alternate reproduction of 
the lower animals, is sufficient to undermine the old theory 
of Spontaneous Generation, which was proposed to account 
for the presence of worms in the bodies of animals, for the 
sudden appearance of myriads of animalcules in stagnant 
water, and under other circumstances rendering their pre- 
sence mysterious. We need only to recollect how the 

Cercaria insinuates itself into the 
skin and the viscera of mollusks 
(339, 342), to understand how ad- 


mission may be gained to the most 
inaccessible parts. Such beings 

Fig. 145. Fig. 146. occur even in the eye of many 

animals, especially of fishes ; they are numerous in the 
eye of the common fresh-water perch of Europe. To the 
naked eye they seem like little white spots (Fig. 145) ; but 
when magnified they have the form of Fig. 146. 

362. As to the larger intestinal worms found in other 
animals, the mystery of their origin has been entirely 
solved by recent researches. A single instance will illus- 
trate their history. At certain periods of the year, the 
Sculpins of the Baltic are infested by a particular species of 
Tsenia or tape-worm, from which they are free at other 
seasons. Mr. Eschricht, found, that at certain seasons, the 
worms lose a great portion of the long chain of rings of 
which they are composed. On a careful examination, he 
found that each ring contained several hundred eggs, which, 
on being freed from their envelop, floated in the water. 
As these eggs are innumerable, it is not astonishing that the 
Sculpins should occasionally swallow some of them with 


their prey. The eggs, being thus introduced into the stom- 
ach of the fish, find conditions favorable to their develop- 
ment ; and thus the species is propagated, and at the same 
time transmitted from one generation of the fish to another. 
The eggs which are not swallowed are probably lost. 

363. All animals swallow, in the same manner, with 
their food, and in the water they drink, numerous eggs of 
such parasites, any one of which, finding in the intestine of 
the animal favorable conditions, is hatched. It is probable 
that each animal affords the proper conditions for some par- 
ticular species of worm ; and thus we may explain how it is 
that most animals have parasites peculiar to themselves. 

364. As respects the Infusoria, we also know that most 
of them lay eggs. These eggs which are extremely minute, 
(some of them are only T^-^IJ f an inch in diameter), are 
scattered everywhere in great profusion, in water, in the air, 
in mist, and even in snow. Assiduous observers have not 
only seen the eggs laid, but moreover, have followed their 
development, and have seen the young animal forming in 
the egg, then escaping from it, increasing in size, and, in its 
turn, laying eggs. They have been able, in some instances, 
to follow them even to the fifth and sixth generation. 

365. This being the case, it is much more natural to sup- 
pose that all the Infusoria are products of like germs, than 
to assign to them a spontaneous origin altogether incompati- 
ble with what we know of organic development. Their 
rapid appearance is not at all astonishing, when we reflect 
that some mushrooms attain a considerable size in a few 
hours, but yet pass through all the phases of regular growth ; 
and, indeed, since the knowledge of the different modes of 
generation among the lower animals, no substantial difficul- 
ties to the axiom " omne vivum ex ovo " (275), any longer 



366. UNDER the name of metamorphoses are included 
those changes which the body of an animal undergoes after 
its birth, and which modify, in various degrees, its organiza- 
tion, form, and even its mode of life. Such modifications 
are not peculiar to certain classes, as has been so long sup- 
posed, but are common to all animals, without exception. 

367. Vegetables also undergo metamorphoses, but with 
this essential difference, that in vegetables the process con- 
sists in an addition of new parts to the old ones. A succes- 
sion of leaves, differing from those which preceded them, 
comes on each season ; branches and roots are added to 
the old stem, and woody layers to the trunk. In animals, 
the whole body is transformed, in such a manner that all the 
existing parts go to make up a new body. The chrysalis 
becomes a butterfly ; the frog, after having been herbivorous 
during its tadpole state, becomes carnivorous, and its stom- 
ach is accommodated to a new mode of life ; at the same 
time, instead of breathing by gills, it becomes an air-breath- 
ing animal ; its tail and the gills disappearing, and legs be- 
ing formed. 

368. The nature, the duration, and the importance of 
metamorphoses, and also the epoch at which they take 
place, are subjected to infinite variations. The most striking 
changes which naturally present themselves to the mind 


when we speak of metamorphoses, are those of insects. 
Not merely is there a change of physiognomy and form, or 
the possession of an organ more or less, but their whole or- 
ganization is modified. The animal enters into new rela- 
tions with the external world ; and at the same time, new 
instincts are imparted to it. It has lived in water, and re- 
spired by gills ; it is now furnished with a windpipe, and 
breathes air. It passes by, with indifference, objects which 
before were attractive, and its new instincts prompt it to seek 
conditions which would have been most pernicious during 
its former period of life. All these changes are brought 
about without destroying the individuality of the animal. 
The mosquito, which to-day haunts us with its shrill trum- 
pet, and pierces us for our blood, is the same animal that 
a few days ago lived obscure and unregarded in stagnant 
water, under the guise of a little worm. 

369. Every one is familiar with the metamorphoses of the 
silk- worm. On escaping from the egg, the little worm 
or caterpillar grows with great rapidity for twenty days, 
when it ceases to feed, spins its silken cocoon, casts its 
skin, and remains enclosed in its chrysalis state.* During 
this period of its existence most extraordinary changes 
take place. The jaws with which it masticated mulberry 
leaves are exchanged for a coiled tongue ; the spinning 
organs disappear ; the gullet is lengthened and more 
slender; the stomach, which was nearly as long as the 
body, is now contracted into a circular bag ; the intes- 
tine, on the contrary, becomes elongated and tortuous, 
having also one portion much smaller than the other. 
The dorsal vessel is also shortened. The ganglions near 
the head approach each other, and unite into a single 

* In the raising of silk-worms this period is not waited for, but the ani- 
mal is killed as soon as it has spun its cocoon. 


mass in the chest. Antennas and palpi are developed on 
the head, and simple eyes are exchanged for compound ones. 
The muscles, which before were uniformly distributed (159), 
are now gathered into masses. The limbs are elongated, 
and wings spring out from the thorax. More active motions 
then reappear in the digestive organs, and the animal, 
bursting the envelop of its chrysalis, issues in the form of 
a winged moth. 

370. The different external forms which an insect may 
assume is well illustrated by one which is unfortunately too 
well known in this country, namely, the canker-worm. Its 
eggs are laid near the tips of the small branches of the 
apple-tree, elm, and some other trees. They are hatched 
about the time the tender leaves of these trees begin to unfold. 

a b c d 

Fig. 147. 

The caterpillar (a) feeds on the leaves, and attains its full 
growth at the end of about four weeks, being then not quite 
an inch in length. It then descends to the ground, and 
enters the earth to the depth of four or five inches, and 
having excavated a sort of cell, is soon changed into a chry- 
salis or nymph (&). At the usual time in the spring, it bursts 
the skin, and appears in its perfect state, under the form 
of a winged moth (d). In this species, however, only the 
male has wings. The perfect insects soon pair, the female 
(c) crawls up a tree and deposits her eggs, and then dies. 

371. Transformations no less remarkable are observed 
among the Crustacea. The metamorphoses in the family Cir- 
rhipedes are especially striking. It is now known that the 
barnacles (Balanus), which have been arranged among the 



mollusks are truly crustaceans ; and this result of modern 
researches is confirmed in the clearest manner by the study 
of their transformations. The following figures represent 
the different phases of the duck-barnacle (Anatifa). 

d Fig. 148. e 

372. The Anatifa, like all Crustacea, is reproduced by 
eggs, specimens of which, magnified ninety diameters, are 
represented in figure 148, a. From these eggs little ani- 
mals issue which have not the slightest resemblance to the 
parent. They have an elongated form (Z>), a pair of ten- 
tacles, and four legs, with which they swim freely in the 

373. Their freedom, however, is of but short duration. 
The little animal soon attaches itself by means of its tenta- 
cles, having previously become covered with a transparent 
shell, through which the outlines of the body, and also a very 
distinct eye, are easily distinguished (Fig. 148, c). Figure 
148, d, shows the animal taken out of its shell. It is plainly 
seen that the anterior portion has become considerably 
enlarged. Subsequently, the shell becomes completed, 
and the animal casts its skin, losing with it both its eyes 
and its tentacles. On the other hand, a thick membrane 
lines the interior of the shell, which pushes out and forms 
astern (e), by means of which the animal fixes itself to 




marine bodies, after the loss of its tentacles. This stem 
gradually enlarges, and the animal soon acquires a definite 
shape, such as it is represented in figure 148, f, attached to 
a piece of floating wood. 

374. There is, consequently, not only a change of organi- 
zation in the course of the metamorphoses, but also a change 
of faculties and mode of life. The animal, at first free, 
becomes fixed ; and its adhesion is effected by totally 
different organs at different periods of life, first by means of 
tentacles, which were temporary organs, and afterwards 
by means of a fleshy stem designed especially for that 

375. The Radiata also furnish us with examples of vari- 
ous metamorphoses, especially among the star-fishes. A 
small species living on the coast of New England (Echi- 
naster sanguinolentus) undergoes the following phases 
(Fig. 149). 

Fig. 149. 

376. If the eggs are examined by the microscope, each 
one is found to contain a small, pear-shaped body, which 
is the embryo (e), surrounded by a transparent envelop. 
On escaping from the egg, the little animal has an ob- 
long form with a constriction at the base. This con- 
striction becoming deeper and deeper forms a pedicle, 
(p), which soon divides into three lobes. The disc also 
assumes a pentagonal form, and five double series of vesi- 
cles, which are the first rudiments of the rays, are seen 
to form in the interior of the pentagon. At the same time, 
the peduncle contracts still more, and at last is entirely 
absorbed into the cavity of the body, and the animal soon 
acquires its final form (m). 



377. Analogous transformations take place in the Comat- 
ula. In early life 
(Fig. 150) it is 
fixed to the ground 
by a stem, but be- 
comes detached at 
a certain epoch, 
and then floats 
freely in the sea 
(Fig. 151). On 
the other hand, Fi =- 151 

the Polypi seem to follow a reverse course, 
many of them becoming fixed to the earth 
after having been previously free. 

Fig. iso. 378. The metamorphoses of mollusks, 

though less striking, are not less worthy of notice. Thus, 
the oyster, with which we are familiar in its adhering shell, 
is free when young, like the clam (Mya) and most other 
shell-fishes. Others, which are at first attached or sus- 
pended to the gills of the mother, afterwards become free, 
as the Unio. Some naked Gasteropods, the Acteon or the 
Eolis, for example, are born with a shell, which they 
part with, shortly after leaving the egg. 

379. The study of metamorphosis is therefore of the ut- 
most importance for understanding the real affinities of ani- 
mals very different in appearance, as is readily shown by 
the following instances. The butterfly and the earth-worm 
seem, at the first glance, to have no relation whatever. 
They differ in their organization no less than in their out- 
ward appearance. But if we compare the caterpillar and 
the worm, these two animals closely resemble each other. 
The analogy however, is only transient ; it lasts only 
during the larva state of the caterpillar, and is effaced as it 
passes to the chrysalis and butterfly states. The latter be- 


comes a more and more perfect animal, whilst the worm 
remains in its inferior state. 

380. Similar instances are furnished by animals belong- 
ing to all the types of the Animal Kingdom. Who would 
think, at the first glance, that a Barnacle or an Anatifa were 
more nearly allied to the crabs than to the oyster ? And, 
nevertheless, we have seen (372), in tracing back the Anat- 
ifa to its early stages, that it then bears a near resemblance 
to a little Crustacean (Fig. 148, d). It is only when full 
grown that it assumes its peculiar mollusk-like covering. 

381. Among the Cuttle-fishes there are several, the 
Loligo (Fig. 47) for example, which are characterized by 
the form of their tentacles, the two interior being much 
longer than the others, and of a different form ; whilst 
in others, as the Octopus, they are all equal. But if we com- 
pare the young, we find that in both animals the tentacles 
are all equal, though they differ in number. The inequality 
in the tentacles is the result of a further development. 

382. Among the Radiata, the Pentacrinus and the Comat- 
ula exemplify the same point. The two are very different 
when full grown, the latter being a free-swimming star-fish 
(Fig. 151), while the former is attached to the soil, like a 
Polyp. But we have seen (377) that the same is the case 
with Comatula in its early period ; and that in consequence 
of a further metamorphosis, it becomes disengaged from its 
stem, and floats freely in the water. 

383. In the type of Vertebrates, the considerations drawn 
from metamorphoses acquire still greater importance in re- 
ference to classification. The Sturgeon and the White-fish 
before mentioned (306) are two very different fishes ; yet, 
taking into consideration their external form and bearing 
merely, it might be questioned which of the two should 
take the highest rank ; whereas, the doubt is very easily 
resolved by an examination of their anatomical structure. 



The White-fish has a skeleton, and moreover, a vertebral 
column composed of firm bone. The Sturgeon (Fig. 152), 

Fig. 152. 

on the contrary, has no bone in the vertebral column, except 
the spines or apophyses of the vertebra. The middle part, 
or body of the vertebra, is cartilaginous ; the mouth is 
transverse, and underneath the head ; and the caudal fin 
is unequally forked, while in the White-fish it is equally 

384. If, however, we observe the young White-fish just 
after it has issued from the egg (Fig. 123), the contrast will 
be less striking. At this period the vertebrae are cartilagi- 
nous, like those of the Sturgeon ; its mouth also is trans- 
verse, and its tail undivided ; at that period the White-fish 
and the Sturgeon are therefore much more alike. But this 
similarity is only transient ; as the White-fish grows, its ver- 
tebrae become ossified, and its resemblance to the Sturgeon 
is comparatively slight. As the Sturgeon has no such 
transformation of the vertebra, and is in some sense ar- 
rested in its development, while the White-fish undergoes 
subsequent transformation, we conclude that, compared with 
the White-fish, it is really inferior in rank. 

385. This relative inferiority and superiority strikes us 
still more, when we compare with our most perfect fishes 
(the Salmon, the Cod) some of those worm-like animals, so 
different from ordinary fishes that they were formerly placed 

among the worms. The Am- 
phioxus, represented of its natu- 
153. m l size (Fig. 153), not only 

has no bony skeleton, but not even a head, properly 



speaking. Yet the fact that it possesses a dorsal cord, 
extending from one extremity of the body to the other, 
proves that it belongs to the type of Vertebrates. But as 
this peculiar structure is found only at a very early period 
of embryonic development, in other fishes, we conclude that 
the Amphioxus holds the very lowest rank in this class. 

386. Nevertheless, metamorphoses will not indicate the 
true measure of the perfection of animals, if limited to those 
changes which take place after birth ; because there are 
many animals which undergo no changes of great impor- 
tance after their escape from the egg, and occupy, neverthe- 
less, a high rank in the Zoological series, as for example, 
Birds and many Mammals. The question now is, whether 
such animals are developed according to different plans, 
or whether their dissimilarity in that respect is merely appa- 
rent, arising from an incorrect interpretation. To answer 
this question, let us go back to the period anterior to 
birth, and see if some connection may not be made out 
between embryonic changes, and metamorphoses which 
take place subsequently. 

387. We have already shown that embryonic devel- 
opment consists in a series of transformations ; the young 
animal enclosed in the egg differing, at each period of its de- 
velopment, from what it was in the preceding period. But 
because these transformations precede birth, and are there- 
fore not easily observed, does not make them the less 
important. To be satisfied that these transformations are 
real metamorphoses, in every respect similar to those 
which follow birth, we have only to compare, on the other 
hand, those changes which immediately precede birth with 
those which immediately follow it, and we shall readily 
perceive that the latter are simply a continuation of the 
former, till all are completed. 

388. Let us recur to the development of fishes for illus- 


tration. The young White-fish, as we have seen (315), 
is far from having acquired its complete development, 
when born. The vertical fins are not yet separate ; the 
mouth has not yet its proper position ; the yolk has not 
yet retreated within the cavity of the body, but hangs below 
the chest in the form of a large vesicle. Much therefore 
remains to be done, in order to complete its development. 
But the fact of its being born does not prevent its future 
evolution, which goes on without interruption. 

389. Similar inferences may be drawn from the develop- 
ment of the chicken. The only difference is that the young 
chicken is born in a more complete state, the most impor- 
tant transformations having taken place during the embry- 
onic period, while those to be undergone after birth are less 
considerable, though they complete the process begun in the 
embryo. Thus we see it, shortly after birth, completely 
changing its covering, and clothed with feathers instead of 
down ; still later its crest appears, and its spurs begin to be 

390. In certain Mammals, known under the name of 
Marsupials (the Opossum and Kangaroo), the link between 
the metamorphoses which take place before birth, and those 
that occur at a later period, is especially remarkable. These 
animals are brought into the world so weak and undeveloped 
that they have to undergo a second gestation, in a pouch 
with which the mother is furnished, and in which the young 
remain, each one fixed to a teat, until they are entirely de- 
veloped. Even those animals which are born nearest to the 
complete state have, nevertheless, transformations to un- 
dergo. Ruminants acquire their horns ; and the lion his 
mane. Most mammals, at birth, are destitute of teeth, and 
incapable of using their limbs ; and all are dependent on 
the mother and the milk secreted by her, until the stomach 
is capable of digesting other aliment. 


391. If it be thus shown that the transformations which 
take place in the embryo are of the same nature and of the 
same importance as those which occur afterwards, the cir- 
cumstance that some precede and others succeed birth, can- 
not make any radical distinction between them. Both are 
processes of the life of the individual. Now, as life does not 
commence at birth, but goes still farther back, it is quite clear 
that the modifications which supervene during the former 
period are essentially the same as the later ones ; and, 
hence, that metamorphoses, far from being an exception in 
the Animal Kingdom, are one of its general features. 

392. We are therefore perfectly entitled to say that all 
animals, without exception, undergo metamorphoses. Were 
it not so, we should be at a loss to conceive why animals of 
the same division present such wide differences ; and that 
there should be, as in the class of Reptiles, some families 
that undergo important metamorphoses, (the frogs, for ex- 
ample), and others in which nothing of the kind is known, 
(the Lizards and Tortoises). 

393. It is only by connecting the two kinds of transforma- 
tion, namely, those which take place before, and those after 
birth, that we are furnished with the means of ascertaining 
the relative perfection of an animal ; in other words, 
these transformations become, under such circumstances, a 
natural key to the gradation of types. At the same time, 
they will force upon us the conviction that there is an immu- 
table principle presiding over all these changes, and regu- 
lating them in a peculiar manner in each animal. 

394. These considerations are important, not only from 
their bearing on classification, but not less so from the ap- 
plication which may be made of them to the study of fossils. 
If we examine attentively the fishes that have been found 
in the different strata of the earth, we remark that those of 
the most ancient deposits have in general preserved only the 


apophyses of their vertebrae, whilst the vertebrae themselves 
are wanting. It would be the same, were the Sturgeons of 
one of the American rivers to become petrified. As the 
apophyses are the only bony portions of the vertebral 
column, they alone would be preserved. Indeed, fossil 
Sturgeons are known, which are in precisely this condition. 
395. From the fact above stated, we may conclude 
that the oldest fishes have not passed through all the 
metamorphoses which our osseous fishes undergo, and 
consequently that they are inferior to analogous species 
of the present epoch, which have bony vertebras. Simi- 
lar considerations apply to the fossil Crustacea and to the 
fossil Echinoderms, when compared with the living ones, 
and will probably be true of all classes of the Animal King- 
dom, when fully studied as to their geological succession. 





396. No animal, excepting man, inhabits every part of 
the surface of the earth. Each great geographical or cli- 
matal region is occupied by some species not found else- 
where ; and each animal dwells within certain limits, beyond 
which it does not range while left to its natural freedom, and 
within which it always inclines to return, when removed by 
accident or design. Man alone is a cosmopolite. His domain 
is the whole earth. For him, and with a view to him, it was 
created. His right to it is based upon his organization and 
his relation to Nature, and is maintained by his intelligence 
and the perfectibility of his social condition. 

397. A group of animals which inhabits any particular 
region, embracing all the species, both aquatic and terrestrial, 
is called its FAUNA ; in the same manner as the plants of a 
country are called its Flora. To be entitled to this name, it 
is not necessary that every animal in the group should be 
different from those inhabiting any other region ; it is suffi- 
cient that there should be peculiarities in the distribution of 
the families, genera, and species, and in the preponderance 


of certain types over others, sufficiently prominent to impress 
upon the group well-marked features. Thus, for example, 
in the islands of the Pacific are found terrestrial animals, 
altogether peculiar, and not found on the nearest continents. 
There are numerous animals in New Holland differing from 
any found on the continent of Asia, or, indeed, on any other 
part of the earth. If, however, some species inhabiting both 
shores of a sea which separates two terrestrial regions, are 
found to be alike, we are not to conclude that those regions 
have the same Fauna, any more than that the Flora of Lap- 
land and England are alike, because some of the sea-weeds 

o ' 

found on both shores are the same. 

398. There is an evident relation between the fauna of 
any locality and its climate ; and, on that account, the 
faunas of the two hemispheres have been distributed into 
three principal divisions, namely, the arctic, the temperate, 
and the tropical faunas ; in the same manner as we have 
arctic, temperate, and tropical floras. Hence also, ani- 
mals dwelling at high elevations upon mountains, where the 
temperature is much reduced, resemble the animals of 
colder latitudes, rather than those of the surrounding plains. 

399. In some respects, the peculiarities of the fauna of a 
region depends upon its flora, at least so far as land animals 
are concerned ; for herbivorous animals will exist only 
where there is an adequate supply of vegetable food. But 
taking the terrestrial and aquatic animals together, the distri- 
bution of a fauna is less intimately dependent on climate 
than that of a flora. Plants, in truth, are for the most part 
terrestrial (marine plants being relatively very few), while 
animals are chiefly aquatic. The ocean is the true home 
of the Animal Kingdom ; and while plants, with the excep- 
tion of the lichens and mosses, become dwarfed or perish 
under the influence of severe cold, the sea teems with 
animals of all classes, far beyond the extreme limit of 
flowering plants. 


400. The influence of climate, in the polar regions, acts 
merely to induce a greater uniformity in the species of 
animals. Thus the same animals inhabit the polar regions of 
the three continents. The polar bear is the same in Europe, 
Asia, and America, and so are also a great many birds. 
In the temperate regions, on the contrary, the species 
differ on each of the continents, but they still preserve the 
same general features. The types are the same, but they 
are represented by different species. In consequence of 
these genera] resemblances, the first colonists of New 
England erroneously applied the names of European 
species to American animals. Similar differences are 
observed as to regions of the same continent, within the 
same parallels of latitude. The animals of Oregon and 
of California are not the same as those of New England. 
The difference, in certain respects, is even greater than 
between the animals of New England and Europe, as the 
researches of the naturalists of the United States Exploring 
Expedition have proved. In like manner, the animals of 
temperate Asia differ more from those of Europe than 
they do from those of America. 

401. Under the torrid zone, the Animal Kingdom, as well 
as the Vegetable, attains its highest development. The ani- 
mals of the tropics are not only different from those of the 
temperate zone, but, moreover, they present the greatest va- 
riety among themselves. The most gracefully proportioned 
forms are found by the side of others the most odd, decked 
with every combination of the most brilliant coloring. At the 
same time, the contrast between the animals of different 
continents is more marked ; and in many respects, the ani- 
mals of the different tropical faunas differ not less among 
themselves than they do from those of the temperate or 
frozen zones. Thus, the fauna of Brazil is quite as differ- 
ent from that of Central Africa as it is from that of the Uni- 
ted States. 


402. This diversity upon different continents cannot de- 
pend simply on any influence of the climate of the tropics ; 
if it were so, uniformity ought to be restored in proportion 
as we recede from the tropics towards the antarctic tem- 
perate regions. But, instead of this, the differences con- 
tinue to increase ; so much so, that no faunas are more in 
contrast than those of Cape Horn, the Cape of Good Hope, 
and New Holland. Hence other influences must be in ope- 
ration besides those of climate; influences of a higher 
order, which are involved in a general plan, and intimately 
associated with the development of life on the surface of 
the earth. 

403. Faunas are more or less distinctly limited, according 
to the natural features of the earth's surface. Sometimes 
two faunas are separated by an extensive chain of moun- 
tains, like the Rocky Mountains. Again, a desert may in- 
tervene, like the desert of Sahara, which separates the 
fauna of Central Africa from that of the Atlas and the Moor- 
ish coast, the latter of which is merely an appendage to the 
fauna of Europe. But the sea effects the most complete 
separation. The depths of the ocean are quite as impassa- 
ble for marine species as high mountains are for terrestrial 
animals. It would be quite as difficult for a fish or a mollusk 
to cross from the coast of Europe to the coast of America, 
as it would be for a reindeer to pass from the arctic to the 
antarctic regions, across the torrid zone. Experiments of 
dredging in very deep water have also taught us that the 
abyss of the ocean is nearly a desert. Not only are no 
materials found there for sustenance, but it is doubtful if ani- 
mals could sustain the pressure of so great a column of 
water, although many of them are provided with a system 
of pores (260), which enables them to sustain a much greater 
pressure than terrestrial animals. 

404. When there is no great natural limit, the transition 



from one fauna to another is made insensibly. Thus, in 
passing from the arctic to the temperate regions of North 
America, one species takes the place of another, a third 
succeeds the second, and so on, until finally the fauna is 
found to be an entirely new one, without its being always 
possible to mark the precise limit between the two. 

405. The range of species does not at all depend upon 
their powers of locomotion ; if it were so, animals which 
move slowly and with difficulty would have a narrow range, 
whilst those which are very active would be widely diffused. 
Precisely the reverse of this is actually the case. The com- 
mon oyster extends at least from Cape Cod to the Carolinas ; 
its range is consequently very great ; much more so than that 
of some of the fleet animals, as, for instance, the Moose. It 
is even probable that the very inability of the oyster to 
travel, really contributes to its diffusion, inasmuch as being 
once removed, it is difficult for it to return ; and more- 
over, being fixed, and consequently unable to choose posi- 
tions for its eggs, they must be left to the mercy of currents ; 
while Fishes, by depositing their eggs in the bays and inlets 
of the shore, undisturbed by currents and winds, secure 
them from too wide a dispersion. 

406. The nature of their food has an important bearing 
upon the grouping of animals, and upon the extent of their 
distribution. Carnivorous animals are generally less con- 
fined in their range than herbivorous ones ; because their 
food is almost everywhere to be found. The herbivora, on 
the other hand, are restricted to the more limited regions 
corresponding to the different zones of vegetation. The 
same remark may be made with respect to Birds. Birds of 
prey, like the eagle and vulture, have a much wider 
range than the granivorous and gallinaceous birds. Still, 
notwithstanding the facilities they have for change of place, 
even the birds that wander widest recognize limits which 


they do not overpass. The Condor of the Cordilleras does 
not descend into the temperate regions of the United States ; 
and yet it is not that he fears the cold, since he is frequently 
known to ascend even above the highest summits of the 
Andes, and disappears from view where the cold is most 
intense. Nor can it be from lack of prey. 

407. Again, the peculiar configuration of a country 
sometimes determines a peculiar grouping of animals, into 
what may be called local faunas. Such, for example, are 
the prairies of the West, the Pampas of South America, the 
Steppes of Asia, the Deserts of Africa ; and for marine 
animals, the basin of the Caspian. In all these localities, 
animals are met with which exist only there, and are not 
found except under those particular conditions. 

408. Finally, to obtain a true picture of the zoological 
distribution of animals, not the terrestrial types alone, but 
the marine species must also be included. Notwithstanding 
the uniform nature of the watery element, the animals which 
dwell in it are not dispersed at random ; and though the 
limits of the marine may be less easily defined than those of 
the terrestrial fauna, still, marked differences of the animals 
in the great basins are not less observable. Properly to ap- 
prehend how marine animals may be distributed into local 
faunas, it must be remembered that their residence is not in 
the high sea, but along the coasts of continents and on sound- 
ings. It is on the Banks of Newfoundland, and not in the 
deep sea, that the great cod-fishery is carried on ; and it is 
well known that when fishes migrate, they take care to run 
along the shores. The range of marine species being there- 
fore confined to the vicinity of the shores, their distribution 
must be subjected to laws similar to those which regulate the 
terrestrial faunas. As to the fresh-water fishes, not only do 
the species vary in the different zones, but even the different 
rivers of the same region have species peculiar to them, and 
not found in neighboring streams. 


409. A very influential cause in the distribution of aquatic 
animals is the depth of the water. The Mollusks, and even 
the Fishes found near the surface between high and low 
water differ, in general, from those living at the depth of 
twenty or thirty feet, and these again are found to be differ- 
ent from those which are met with at a greater depth. Their 
coloring, in particular, varies, according to the quantity of 
light they receive, as has also been shown to be the case 
with the marine plants. 

410. It is sometimes the case that one or more ani- 
mals are found upon a certain chain of mountains, and not 
elsewhere ; as, for instance, the Mountain Sheep (Ovis 
montana), upon the Rocky Mountains, or the Chamois and 
the Ibex upon the Alps. The same is also the case on 
some of the wide plains or prairies. This, however, does 
not entitle such regions to be considered as having an inde- 
pendent fauna, any more than a lake is to be regarded as 
having a peculiar fauna, exclusive of the animals of the 
surrounding country, merely because some of the spe- 
cies found in the lake may not ascend the rivers emptying 
into it. It is only when the whole group of animals inhabit- 
ing such a region has such peculiarities as to give it a dis- 
tinct character, when contrasted with animals found in sur- 
rounding regions, that it is to be regarded as a separate 
fauna. Such, for example, is the fauna of the great steppe 
or plain of Gobi, in Asia ; and such indeed that of the chain 
of the Rocky Mountains may prove to be, when the animals 
inhabiting them are better known. 

411. The migration' of animals might at first seem to 
present a serious difficulty in determining the character 
or the limits of a fauna ; but this difficulty ceases, if we 
regard the country of an animal to be the place where it 
makes its habitual abode. As to Birds, which of all animals 
wander the farthest, it may be laid down as a rule, that they 


belong to the zone in which they breed. Thus, the gulls, 
many of the ducks, mergansers, and divers, belong to the 
boreal regions, though they pass a portion of the year with 
us. On the other hand, the swallows and martins, and 
many of the gallinaceous birds belong to the temperate 
faunas, notwithstanding they migrate during winter to the 
confines of the torrid zone. This rule does not apply to 
the fishes, who annually leave their proper home, and mi- 
grate to a distant region merely for the purpose of spawn- 
ing. The Salmon, for example, comes down from the 
North to spawn on the coasts of Maine and Nova Scotia. 

412. Few of the Mammals, and these mostly of the tribe 
of Rodents, make extensive migrations. Among the most 
remarkable of these are the Kamtschatka rats. In Spring 
they direct their course westward, in immense troops ; and 
after a very long journey, return again in Autumn to their 
quarters, where their approach is anxiously awaited by the 
hunters, on account of the fine furs to be obtained from the 
numerous carnivora which always follow in their train. 
The migrations of the Lemmings are marked by the devas- 
tations they commit along their course, as they come down 
from the borders of the Frozen Ocean to the valleys of 
Lapland and Norway ; but their migrations are not period- 



413. We have stated that all the faunas of the globe 
may be divided into three departments, corresponding to as 
many great climatal divisions, namely, the glacial or arctic, 
the temperate and the tropical faunas. These three divisions 



appertain to both hemispheres, as we recede from the equa- 
tor towards the north or south poles. It will hereafter be 
shown that the tropical and temperate faunas may be again 
divided into several zoological provinces, depending on 
longitude or on the peculiar configuration of the continents. 

414. No continent is better calculated to give a correct 
idea of distribution into faunas, as determined by climate, 
than the continent of America ; extending as it does across 
both hemispheres, and embracing all latitudes, so that all 
climates are represented upon it, as shown by the chart on 
the following page. 

415. Let a traveller embark at Iceland, which is situated 
on the borders of the polar circle, with a view to observe, 
in a zoological aspect, the principal points along the eastern 
shore of America. The result of his observation will be 
very much as follows. Along the coast of Greenland and 
Iceland, and also along Baffin's Bay, he will meet with an 
unvaried fauna composed of the same animals, which are 
also for the most part identical with those of the arctic 
shores of Europe. It will be nearly the same along the 
Labrador coast. 

416. As he approaches Newfoundland, he will see the 
landscape, and with it the fauna, assuming a somewhat 
more varied aspect. To the wide and naked or turfy 
plains of the boreal regions succeed forests, in which he 
will find various animals which dwell only in forests. Here 
the temperate fauna commences. Still the number of spe- 
cies is not yet very considerable ; but as he advances 
southwardly, along the coasts of Nova Scotia and New 
England, he finds these species gradually increasing, while 
those of the cold regions diminish, and at length entirely 
disappear, some few accidental or periodical visitors excepted, 
who wander during winter, as far south as the Carolinas. 

417. But it is after having passed the boundaries of the 
United States, among the Antilles, and more especially on 


:::::::t:::v:::;:. :;::::::: .::.::::;: ::.::::::::::::::::;:: 



I. North Glacial or Arctic. 

II. Northern Temperate. 

III. Northern Warm. 

IV. Tropical. 

V. Southern Warm. 
VI. Southern Temperate. 


the southern continent, along the shores of the Orinoco and 
the Amazon, that our traveller will be forcibly struck with 
the astonishing variety of the animals which people the 
forests, the prairies, the rivers, and the sea-shores, most of 
which he will also find to be different from those of the 
northern continent. By this extraordinary richness of new 
forms, he will become sensible that he is now in the domain 
of the tropical fauna. 

418. Let him still travel on beyond the equator towards 
the tropic of Capricorn, and he will again find the scene 
change as he enters the regions where the sun casts his rays 
more obliquely, and where the contrast of the seasons is 
more marked. The vegetation will be less luxuriant ; the 
palms will have disappeared to make place for other trees ; 
the animals will be less varied, and the whole picture will 
recall to him, in some measure, what he witnessed in the 
United States. He will again find himself in the temperate 
regions, and this he will trace on, till he arrives at the ex- 
tremity of the continent, the fauna and the flora becoming 
more and more impoverished as he approaches Cape Horn. 

419. Finally, we know that there is a continent around 
the South Pole. Although we have as yet but very imper- 
fect notions respecting the animals of this inhospitable 
clime, still the few which have already been observed 
there, all present a close analogy to those of the arctic re- 
gion. It is another glacial fauna, namely, the antarctic. 
Having thus sketched the general distribution of the fauna, 
it remains to point out the principal features of each of 

420. I. ARCTIC FAUNA. The predominant feature of 
the Arctic Fauna is its uniformity. The species are few in 
number ; but, on the other hand, the number of individuals 
is immense. We need only refer to the clouds of birds 
which hover upon the islands and shores of the North ; the 


shoals of fishes, the salmon among others, which throng the 
coasts of Greenland, Iceland, and Hudson's Bay. The 
same uniformity appears in the form and color of the animals. 
There is not a single bird of brilliant plumage, and not a 
fish with varied hues. Their forms are regular, and their 
tints as dusky as the northern heavens. The most conspicu- 
ous animals are the white-bear, the moose, the reindeer, 
the musk-ox, the white-fox, the polar-hare, the lemming, 
and various Seals ; but the most important are the Whales, 
which, it is to be remarked, rank lowest of all the Mam- 
mals. Among the Birds, may be enumerated some sea- 
eagles and a few Waders, with an immense number 
of other aquatic species, such as gulls, cormorants, di- 
vers, petrels, ducks, geese, &c., all belonging to the 
lowest order of Birds. Reptiles are altogether wanting. 
The Articulata are represented by numerous marine worms, 
and by minute crustaceans of the orders Isopoda and Am- 
phipoda. Insects are rare, and of inferior types. Of the 
type of Mollusks, there are Acephala, particularly Tunicata, 
fewer Gasteropods, and very few Cephalopods. Among the 
Radiata are a great number of jelly-fishes, particularly the 
Beroe ; and to conclude with the Echinoderms, there are 
several star-fishes and Echini, but few Holothurise. The 
class of Polypi is very scantily represented, and those pro- 
ducing stony corals are entirely wanting. 

421. This assemblage of animals is evidently inferior to 
that of other faunas, especially to those of the tropics. Not 
that there is a deficiency of animal life ; for if the spe- 
cies are less numerous, there is a compensation in the 
multitude of individuals, and also in this other very sig- 
nificant fact, that the largest of all animals, the whales, 
belong to this fauna. 

422. It has already been said (400) that the arctic fauna 
of the three continents is the same ; its southern limit, how- 


ever, is not a regular line. It does not correspond precisely 
with the polar circle, but rather to the isothermal zero, that 
is, the line where the average temperature of the year is 
at 32 of Fahrenheit. The course of this line presents 
numerous undulations. In general, it may be said to coin- 
cide with the appearance of trees, so that it passes 
where forest vegetation succeeds the vast arid plains, the 
barrens of North America, or the tundras of the Samoyedes. 
The uniformity of these plains involves a corresponding 
uniformity of plants and animals. On the North American 
continent it extends much farther southward on the east- 
ern shore, than on the western. From the peninsula of 
Alashka it bends northwards towards the Mackenzie, then 
descends again towards the Bear Lake, and comes down 
to near the northern shore of Newfoundland. 

423. II. TEMPERATE FAUNAS. The faunas of the tem- 
perate regions of the northern hemisphere are much more 
varied than that of the arctic zone. Instead of consisting 
mainly of aquatic tribes, we have a considerable number 
of terrestrial animals of graceful form, animated appearance, 
and varied colors, though less brilliant than those found in 
tropical regions. Those parts of the country covered with 
forests especially swarm with insects, worms, terrestrial and 
fluviatile mollusks, which become the food of still other 

424. Still, the climate is not sufficiently warm over the 
whole extent of this zone to allow the trees to retain their 
foliage throughout the year. At its northern margin the 
leaves, excepting those of the pines and spruces, fall, on 
the approach of the cold season, and vegetation is ar- 
rested for a longer or shorter period. Insects retire, 
and the animals which live upon them no longer find 
nourishment, and are obliged to migrate to warmer re- 
gions, on the borders of the tropics, where, on the ever- 
verdant vegetation, they find the means of subsistence. 


425. Some of the herbivorous Mammals, the Bats, and 
the reptiles which feed on insects, pass the winter in a state 
of torpor, from which they awake in spring. Others retire 
into dens, and live on the provisions they have stored up 
during the warm season. The Carnivora, the Ruminants, 
and the most active portion of the Rodents, are the only 
animals that do not change either their abode or their 
habits. The fauna of the temperate zone thus presents an 
ever-changing picture, which may be considered as one of 
its most important features, since these changes recur with 
equal constancy in the Old and the New World. 

426. Taking the contrast of the vegetation, as a basis, 
and the consequent changes of habit imposed upon the 
denizens of the forests, the temperate fauna has been 
divided into two regions ; a northern one, where the 
trees, except the pines, drop their leaves in winter, and 
a southern one, where they are evergreen. Now, as 
the limit of the former, that of the deciduous trees, coin- 
cides, in general, with the limit of the pines, it may be 
said that the cold region of the temperate fauna extends as 
far as the pines. In the United States this coincidence is 
not so marked as in other regions, inasmuch as the pines 
extend into Florida, while they do not prevail in the West- 
ern States ; but we may reckon as belonging to the southern 
portion of the temperate region, that part of the country south 
of the latitude where the Palmetto or Cabbage-tree (Cha- 
mczrops) commences, namely, all the States to the south of 
North Carolina ; while the States to the north of this limit 
belong to the northern portion of the temperate region. 

427. This division into two zones is supported by obser- 
vations made on the maritime faunas of the Atlantic coast. 
The line of separation between them, however, being influ- 
enced by the Gulf Stream, is considerably farther to the 
north; namely, at Cape Cod. It has been ascertained 
that of one hundred and ninety-seven Mollusks inhabiting the 


coast of New England, fifty do not pass to the north of Cape 
Cod, and eighty-three do not pass to the south of it ; only 
sixty-four being common to both sides of the Cape. A 
similar limitation of the range of Fishes has been noticed 
by Dr. Storer ; and Dr. Holbrook has found the Fishes of 
South Carolina to be different from those of Florida and the 
West Indies. In Europe, the northern part of the temperate 
region extends to the Pyrennees and the Alps ; and its 
southern portion consists of the basin of the Mediterranean, 
together with the northern part of Africa, as far as the 
desert of Sahara. 

428. A peculiar characteristic of the faunas of the tem- 
perate regions in the northern hemisphere, when contrasted 
with those of the southern, is the great similarity of the 
prevailing types on both continents. Notwithstanding the 
immense extent of country embraced, the same stamp 
is everywhere exhibited. Generally, the same families, 
frequently the same genera, represented by different spe- 
cies, are found. There are even a few species of terres- 
trial animals regarded as identical on the continents of 
Europe and America ; but their supposed number is con- 
stantly diminished, as more accurate observations are made. 
The predominant types among the mammals are the bison, 
deer, ox, horse, hog, numerous rodents, especially squirrels, 
and hares, nearly all the insectivora, weasels, martens, 
wolves, foxes, wild cats, &c. On the other hand, there are 
no Edentata and no Quadrumana, with the exception of 
some monkeys on the two slopes of the Atlas. Among 
Birds, there is a multitude of climbers, passerine, gallina- 
ceous, and many rapacious birds. Of Reptiles, there 
are lizards and tortoises of small or medium size, ser- 
pents, and many batrachians, but no crocodiles. Of Fishes, 
there is the trout family, the cyprinoids, the sturgeons, the 
pikes, the cod, and especially the great family of Herrings 
and Scomberoids, to which latter belong the mackerel and 


the tunny. All classes of the Mollusks are represented ; 
though the cephalopods are less numerous than in the torrid 
zone. There is an infinite number of Articulata of every 
type, as well as numerous Polyps, though the corals proper 
do not yet appear abundantly. 

429. On each of the two continents of Europe and Amer- 
ica, there is a certain number of species which extend from 
one extreme of the temperate zone to the other. Such, for 
example, are the deer, the bison, the cougar, the flying-squir- 
rel, numerous birds of prey, several tortoises, and the rattle- 
snake, in America. In Europe, the brown bear, wolf, 
swallow, and many birds of prey. Some species have a 
still wider range, like the ermine, which is found from 
Bhering's Straits to the Himalaya Mountains, that is to say, 
from the coldest regions of the arctic zone, to the southern 
confines of the temperate zone. It is the same with the 
muskrat, which is found from the mouth of Mackenzie's 
River to Florida. The field-mouse has an equal range in 
Europe. Other species, on the contrary, are limited to one 
region. The Canadian elk is confined to the northern por- 
tion ; and, on the other hand, the prairie wolf, the fox- 
squirrel, the Bassaris and numerous birds, never leave the 
southern portion.* 

430. In America, as in the Old World, the temperate 

* The types which are peculiar to temperate America, and are not found 
in Europe, are the Opossum, several genera of Insectivora, among them 
the shrew-mole (Scalops aquaticus), and the star-nose mole (Condylura 
cristata), which replaces the Mygale of the Old World ; several genera 
of rodents, especially the muskrat. Among the types characteristic of 
America must also be reckoned the snapping-turtle among the tortoises ; 
the Menobranchus and Menopoma, among the Salamanders ; the Gar- 
pike and Amia among the fishes ; and finally among the Crustacea, the 
Limulus. Among the types which are wanting in temperate America, and 
which are found in Europe, may be cited the horse, the wild boar, and the 
true mouse. All the species of domestic mice which live in America, have 
been brought from the Old World. 



fauna is further subdivided into several districts, which may 
be regarded as so many zoological provinces, in each of 
which there is a certain number of animals differing from 
those in the others, though very closely allied. Temperate 
America presents us with a striking example in this respect. 
We have, on the one hand : 

1st. The fauna of the United States properly so called, 
on this side of the Rocky Mountains. 

2d. The fauna of Oregon and California, beyond those 

Though there are some animals which traverse the chain 
of the Rocky Mountains, and are found in the prairies of 
the Missouri as well as on the banks of the Columbia, as, 
for example, the Rocky Mountain deer, (Antilope furci- 
fer), yet if we regard the whole assemblage of animals, 
they are found to differ entirely. Thus, the rodents, part 
of the ruminants, the insects, and all the mollusks, belong 
to distinct species. 

431. The faunas or zoological provinces of the Old World 
which correspond to these are : 

1st. The fauna of Europe, which is very closely related 
to that of the United States proper. 

2d. The fauna of Siberia, separated from the fauna of 
Europe by the Ural Mountains. 

3d. The fauna of the great Asiatic table-land, which, from 
what is as yet known of it, appears to be quite distinct. 

4th. The fauna of China and Japan, which is analogous 
to that of Europe in the Birds, and to that of the United 
States in the Reptiles as it is also in the flora. 

Lastly, it is in the temperate zone of the northern hemi- 
sphere, that we meet with the most striking examples of 
those local faunas which have been mentioned above. 
Such, for example, is the fauna of the Caspian Sea, of the 
steppes of Tartary, and of the Western prairies. 


432. The faunas of the southern temperate regions differ 
from those of the tropics as much as the northern temperate 
faunas do ; and, like them also, may be distinguished into 
two provinces, the colder of which embraces Patagonia. 
But besides differing from the tropical faunas, they are also 
quite dissimilar to each other on the different continents. 
Instead of that general resemblance, that family likeness 
which we have noticed between all the faunas of the tem- 
perate zone of the northern hemisphere, we find here the 
most complete contrasts. Each of the three continental 
peninsulas which jut out southerly into the ocean represents, 
in some sense, a separate world. The animals of South 
America, beyond the tropic of Capricorn, are in all respects 
different from those at the southern extremity of Africa. 
The hyenas, wild-boars, and rhinoceroses of the Cape of 
Good Hope, have no analogues on the American continent ; 
and the difference is equally great between the birds, rep- 
tiles and fishes, insects and mollusks. Among the most 
characteristic animals of the southern extremity of America 
are peculiar species of seals, and especially, among aquatic 
birds, the penguins. 

433. New Holland, with its marsupial mammals, with 
which are associated insects and mollusks no less singular, 
furnishes a fauna still more peculiar, and which does not 
approach those of any of the adjacent countries. In the 
seas of that continent, where every thing is so strange, we 
find the curious shark, with paved teeth and spines on the 
back (Cestracion Philippii}, the only living representative of 
a family so numerous in former zoological ages. But a most 
remarkable feature of this fauna is, that the same types 
prevail over the whole continent, in its temperate as well as 
its tropical portions, the species only being different at dif- 
ferent localities, 



434. TROPICAL FAUNAS. The tropical faunas are dis- 
tinguished, on all the continents, by the immense variety of 
animals which they comprise, not less than by the brilliancy 
of their coverings. All the principal types of animals are 
represented, and all contain numerous genera and species. 
We need only refer to the tribe of humming-birds, which 
numbers not less than 300 species. But what is very im- 
portant is, that here are concentrated the most perfect, 
and also the oddest types of all the classes of the Animal 
Kingdom. The tropical region is the only one occupied by 
the Quadrumana, the herbivorous bats, the great pachyder- 
mata, such as the elephant, the hippopotamus, and the tapir, 
and the whole family of Edentata. Here also are found the 
largest of the cat tribe, the lion and tiger. Among the 
Birds we may mention the parrots and toucans, as essen- 
tially tropical ; among the Reptiles, the largest crocodiles, 
and gigantic tortoises ; and finally, among the articu- 
lated animals, an immense variety of the most beautiful 
insects. The marine animals, as a whole, are equally 
superior to those of other regions ; the seas teem with 
crustaceans and numerous cephalopods, together with an 
infinite variety of gasteropods and acephala. The Echi- 
noderms there attain a magnitude and variety elsewhere 
unknown ; and lastly, the Polyps there display an activity 
of which the other zones present no example. Whole 
groups of islands are covered with coral reefs formed by 
those little animals. 

435. The variety of the tropical fauna is further enriched 
by the circumstance that each continent furnishes new and 
peculiar forms. Sometimes whole types are limited to one 
continent, as the sloth, the toucans, and the humming-birds to 
America, the giraffe and hippopotamus to Africa ; and again, 
animals of the same group have different characteristics, ac- 


cording as they are found on different continents. Thus, 
the monkeys of America, have flat and widely separated 
nostrils, thirty-six teeth, and generally a long, prehensile 
tail. The monkeys of the old world, on the contrary, 
have nostrils close together, only thirty-two teeth, and not 
one of them has a prehensile tail. 

436. But these differences, however important they may 
appear at first glance, are subordinate to more important 
characters, which establish a certain general affinity between 
all the faunas of the tropics. Such, for example, is the fact 
that the quadrumana are limited, on all the continents, to 
the warmest regions ; and never, or but rarely, penetrate into 
the temperate zone. This distribution is a natural conse- 
quence of the distribution of the palms ; for as these trees, 
which constitute the ruling feature of the flora of the trop- 
ics, furnish, to a great extent, the food of the monkeys on 
the two continents, we have only to trace the limits of the 
extent of the palms, to have a pretty accurate indication of 
the tropical faunas on all three continents. 

437. Several well-marked faunas may be distinguished 
in the tropical part of the American continent, namely : 

1. The fauna of Brazil, characterized by its gigantic 
reptiles, its monkeys, its Edentata, its tapir, its humming- 
birds, and its astonishing variety of insects. 

2. The fauna of the western slope of the Andes, com- 
prising Chili and Peru ; and distinguished by its Llamas, 
vicunas, and birds, which differ from those of the basin of the 
Amazon, as also do the insects and mollusks. 

3. The fauna of the Antilles and the Gulf of Mex- 
ico. This is especially characterized by its marine ani- 
mals, among which the Manatee is particularly remarkable ; 
an infinite variety of singular fishes, embracing a large 
number of Plectognaths ; also Mollusks, and Radiata of 



peculiar species. It is in this zone that the Pentacrinus 
caput-medusce. is found, the only representative, in the 
existing creation, of a family so numerous in ancient 
epochs, the Crinoidea with a jointed stem. 

The limits of the fauna of Central America cannot yet 
be well defined from want of sufficient knowledge of the 
animals which inhabit those regions. 

438. The tropical zone of Africa is distinguished by a 
striking uniformity in the distribution of the animals, which 
corresponds to the uniformity of the structure and contour 
of that continent. Its most characteristic species are spread 
over the whole extent of the tropics : thus, the giraffe is met 
with from Upper Egypt to the Cape of Good Hope. The 
hippopotamus is found at the same time in the Nile, the 
Niger, and Orange River. This wide range is the more 
significant as it also relates to herbivorous animals, and thus 
supposes conditions of vegetation very similar, over wide 
countries. Some forms are nevertheless circumscribed 
within narrow districts ; and there are marked differences 
between the animals of the eastern and western shores. 
Among the remarkable species of the African torrid region 
are the baboons, the African elephant, the crocodile of the 
Nile, a vast number of Antelopes, and especially two spe- 
cies of Ourang-outang, the Chimpanzee and the Engeena, 
a large and remarkable animal, recently described by 
Drs. Savage and Wyman. The fishes of the Nile have a 
tropical character, as well as the animals of Arabia, which 
are more allied to those of Africa than to those of Asia. 

439. The tropical fauna of Asia, comprising the two pe- 
ninsulas of India and the isles of Sunda, is not less marked. 
It is the country of the gibbons, the red ourang, the royal 
tiger, the gavial, and a multitude of peculiar birds. Among 
the fishes, the family of Chetodons is most numerously 
represented. Here also are found those curious spiny 


fishes, whose intricate gills suggested the name Labyrinth- 
ici, by which they are known. Fishes with tufted gills are 
more numerous here than in other seas. The insects and 
mollusks are no less strongly characterized. Among others 
is the nautilus, the only living representative of the great 
family of large, chambered-shells which prevailed so exten- 
sively over other types, in former geological ages. 

440. The large island of Madagascar has its peculiar 
fauna, characterized by its makis and its curious rodents. 
It is also the habitat of the Aya-aya. Polynesia, exclusive of 
New Holland, furnishes a number of very curious animals, 
which are not found on the Asiatic continent. Such are the 
herbivorous bats, and the Galeopithecus or flying Maki. 



441. From the survey we have thus made of the distribu- 
tion of the Animal Kingdom, it follows : 

1st. Each grand division of the globe has animals which 
are either wholly or for the most part peculiar to it. These 
groups of animals constitute the faunas of different regions. 

2d. The diversity of faunas is not in proportion to the 
distance which separates them. Very similar faunas are 
found at great distances apart ; as, for example, the fauna 
of Europe and that of the United States, which yet are 
separated by a wide ocean. Others, on the contrary, differ 
considerably, though at comparatively short distances ; as 
the fauna of the East Indies and the Sunda Islands, and that 
of New Holland ; or the fauna of Labrador and that of 
New England. 

3d. There is a direct relation between the richness of a 


fauna and the climate. The tropical faunas contain a much 
larger number of more perfect animals than those of the 
temperate and polar regions. 

4th. There is a no less striking relation between the fauna 
and flora, the limit of the former being oftentimes deter- 
mined, so far as terrestrial animals are concerned, by the 
extent of the latter. 

442. Animals are endowed with instincts and faculties 
corresponding to the physical character of the countries 
they inhabit, and which would be of no service to them 
under other circumstances. The monkey, which is a 
frugivorous animal, is organized for living on the trees 
from which he obtains his food. The reindeer, on the 
contrary, whose food consists of lichens, lives in cold 
regions. The latter would be quite out of place in the 
torrid zone, and the monkey would perish with hunger in 
the polar regions. Animals which store up provisions are 
all peculiar to temperate or cold climates. Their instincts 
would be uncalled for in tropical regions, where the vege- 
tation presents the herbivora with an abundant supply of 
food at all times. 

443. However intimately allied the climate of a country 
may be to the peculiar character of its fauna, we are not to 
conclude that the one is the consequence of the other. 
The differences which are observed between the animals of 
different faunas are no more to be ascribed to the influences 
of climate, than their organization is to the influence of the 
physical forces of nature. If it were so, we should necessa- 
rily find all animals precisely similar, when placed under 
the same circumstances. We shall find, by the study of the 
different groups in detail, that certain species, though very 
nearly alike, are nevertheless distinct in two different faunas. 
Between the animals of the temperate zone of Europe, and 
those of the United States, there is similarity, but not iden- 


tity ; and the particulars in which they differ, though appa- 
rently trifling, are yet perfectly constant. 

444. Fully to appreciate the value of these differences, it 
is often requisite to know all the species of a genus 
or of a family. It is not uncommon to find, upon such an 
examination, that there is often the closest resemblance be- 
tween species that dwell far apart from each other, while 
species of the same genus, that live side by side, are widely 
different. This may be illustrated by a single example. 
The Menopoma, Siren, Amphiuma, Axolotl, and the Meno- 
branchus, are Batrachians which inhabit the rivers and lakes 
of the United States and Mexico. They are very similar in 
external form, yet differ in some of them having external 
gills at the sides of the head, while others have them not; and 
also in having either two or four legs. Hence we might 
be tempted to refer them to different types, did we not know 
intermediate animals, completing the series, namely, the 
Proteus and Megalobatrachus. Now the former exists only 
in the lakes of Austria, and the latter in Japan. The con- 
nection in this case is consequently established by means 
of species which inhabit distant continents. 

445. Neither the distribution of animals therefore, any more 
than their organization, can be the effect of external influ- 
ences. We must, on the contrary, see in it the realization 
of a plan wisely designed, the work of a Supreme Intelli- 
gence who created, at the beginning, each species of animal 
at the place, and for the place, which it inhabits. To each 
species has been assigned a limit which it has no disposition 
to overpass so long as it remains in a wild state. Only 
those animals which have been subjected to the yoke of 
man, or whose subsistence is dependent on man's social 
habits, are exceptions to this rule. 

446. As the human race has extended over the surface of 
the earth, man has more or less modified the animal popu- 


lation of different regions, either by exterminating certain 
species, or by introducing others with which he desires to be 
more intimately associated, the domestic animals. Thus, 
the dog is found wherever we know of the presence of man. 
The horse, originally from Asia, was introduced into Amer- 
ica by the Spaniards ; where it has thrived so well, that 
it is found wild, in innumerable herds, over the Pampas of 
South America, and the prairies of the West. In like 
manner the domestic ox became wild in South America. 
Many less welcome animals have followed man in his peri- 
grinations ; as, for example, the rat and the mouse, as well 
as a multitude of insects, such as the house-fly, the cock- 
roach, and others which are attached to certain species of 
plants, as the white-butterfly, the Hessian-fly, &c. The 
honey-bee also has been imported from Europe. 

447. Among the species which have disappeared, under 
the influence of man, we may mention the Dodo, a pecu- 
liar species of bird which once inhabited the Mauritius, 
some remains of which are preserved in the British and 
Ashmolean Museums ; a large cetacean of the north (Rytina 
Stelleri), which formerly inhabited the coasts of Behring's 
Straits, and which has not been seen since 1768. According 
to all appearances, we must also reckon among these the 
great stag, the skeleton and horns of which have been found 
buried in the peat-bogs of Ireland. There are also many 
species of animals whose numbers are daily diminishing, and 
whose extinction may be foreseen ; as the Canada deer 
(Wapiti] , the Ibex of the Alps, the Lammergeyer, the 
bison, the beaver, the wild-turkey, &c. 

448. Other causes may also contribute towards dispersing 
animals beyond their natural limits. Thus the sea-weeds 
are carried about by marine currents, and are frequently 
met with far from shore, thronged with little crustaceans, 
which are in this manner transported to great distances from 


the place of their birth. The drift-wood which the Gulf 
stream floats from the Gulf of Mexico even to the western 
shores of Europe, is frequently perforated by the larvae of 
insects, and may probably serve as depositories for the eggs 
of fishes, Crustacea and mollusks. It is possible also that 
aquatic birds may contribute in some measure to the diffu- 
sion of some species of fishes and mollusks, either by the 
eggs becoming attached to their feet, or by means of those 
which they evacuate undigested, after having transported 
them to considerable distances. Still, all these circum- 
stances exercise but a very feeble influence upon the distri- 
bution of species in general, and each country, none the less, 
preserves its peculiar physiognomy, so far as its animals are 

449. There is only one way to account for the distribu- 
tion of animals as we find them, namely, to suppose that 
they are autochthonal, that is to say, that they originated 
like plants, on the soil where they are found. In order to 
explain the particular distribution of many animals, we are 
even led to admit that they must have been created at 
several points of the same zone, as we must infer from the 
distribution of aquatic animals, especially that of Fishes. 
If we examine the fishes of the different rivers of the United 
States, peculiar species will be found in each basin, associated 
with others which are common to several basins. Thus, the 
Delaware River contains species not found in the Hudson. 
But, on the other hand, the pickerel is found in both. 
Now if all animals originated at one point, and from a single 
stock, the pickerel must have passed from the Delaware to 
the Hudson, or vice versa, which it could only have been 
done by passing along the sea-shore, or by leaping over large 
spaces of terra firma ; that is to say, in both cases it would 
be necessary to do violence to its organization. Now such 


a supposition is in direct opposition to the immutability of 
the laws of Nature. 

450. We shall hereafter see that the same laws of distri- 
bution are not limited to the actual creation only, but that 
they have also ruled the creations of former geological 
epochs, and that the fossil species have lived and died, most 
of them, in the spot where their remains are found. 

451. Even Man, although a cosmopolite, is subject, in a 
certain sense, to this law of limitation. While he is every- 
where the one identical species, yet several races, marked 
by certain peculiarities of features, are recognized ; such as 
the Caucasian, Mongolian, and African races, of which we 
are hereafter to speak. And it is not a little remarkable, 
that the abiding places of these several races correspond 
very nearly, with some of the great zoological regions. 
Thus we have a northern race, comprising the Samoyedes 
in Asia, the Laplanders in Europe, and the Esquimaux in 
America, corresponding to the arctic fauna (400), and 
like it, identical on the three continents, having for its 
southern limit the region of trees (422). In Africa, 
we have the Hottentot and Negro races, in the south 
and central portions respectively, while the people of 
northern Africa are allied to their neighbors in Europe ; 
just as we have seen to be the case with the zoologi- 
cal fauna in general (403). The inhabitants of New 
Holland, like its animals, are the most grotesque and un- 
couth of all races (433). 

452. The same arrangement holds good elsewhere, 
though not always in so remarkable a degree. In America, 
especially, while the aboriginal race is as well distinguished 
from other races as is its flora, the minor divisions are not 
so decided. Indeed, the facilities, or sometimes we might 
rather say necessities, arising from the varied supplies of 


animal and vegetable food in the several regions, might be 
expected to involve, with his corresponding customs and 
modes of life, a difference in the physical constitution of 
man, which would contribute to augment any primeval dif- 
ferences. It could not indeed be expected, that a people 
constantly subjected to cold, like the people of the North, 
and living almost exclusively on fish, which they cannot 
obtain without great toil and peril, should present the same 
characteristics, either bodily or mental, as those who idly 
regale on the spontaneous bounties of tropical vegetation. 






453. THE records of the Bible, together with human tra- 
dition, teach us that man and the animals associated with 
him were created by the word of God ; " the Lord made 
heaven and earth, the sea, and all that in them is ; ' and 
this truth is confirmed by the revelations of science, which 
unequivocally indicate the direct interventions of creative 

454. But man and the animals which now surround him 
are not the only kinds which have had a being. The surface 
of our planet, anterior to their appearance, was not a desert. 
There are, scattered through the crust of the earth, numerous 
animal and vegetable remains, which show that the earth 
had been repeatedly supplied with, and long inhabited by 
animals and plants altogether different from those now 

455. In general, their hard parts are the only relics of 
them which have been preserved, such as the skeleton and 
teeth of Vertebrates ; the shells of the Mollusks and Radiata ; 


the shields of the Crustaceans, and sometimes the wing-cases 
of Insects. Most frequently they have lost their original 
chemical composition, and are changed into stone ; and 
hence the name of petrifactions or fossils, under which lat- 
ter term are comprehended all the organized bodies of 
former epochs, obtained from the earth's crust. 

456. The study of these remains and of their position in 
the rocks constitutes PALEONTOLOGY ; one of the most essen- 
tial branches of Zoology. Their geological distribution, or 
the order of their successive appearance, namely, the dis- 
tribution of animals in time, is of no less importance than 
the geographical distribution of living animals, of which we 
have treated in the preceding chapter. To obtain an idea 
of the successive creations, and of the stupendous length of 
time they have required, it is necessary to sketch the prin- 
cipal outlines of Geology. 

457. The rocks * which compose the crust of our globe 
are of two kinds : 

1. The Massive Rocks, called also Plutonic or Igneous 
Rocks, which lie beneath all the others, or have some- 
times been forced up through them, from beneath. They 
were once in a melted state, like the lava of the present 
epoch, and on cooling at the surface formed the original 
crust of the globe of granite, porphyry, basalt, &c. 

2. The Sedimentary or Stratified Rocks, called also 
Neptunian Rocks, which have been deposited in water, in 
the same manner as modern seas and lakes deposit sand and 
mud on their shores, or at the bottom. 

458. These sediments have been derived partly from the 
disintegration of the older rocks, and partly from the decay 
of plants and animals. The materials being disposed in 

* Rocks, in a geological sense, include all the materials of the earth, 
the loose soil and gravel, as well as the firm rock. 


layers or strata have become, as they hardened, limestones, 
slates, marls, or grits, according to their chemical and me- 
chanical composition, and contain the remains of the animals 
and plants which were scattered through the waters.* 

459. The different strata, when undisturbed, are ar- 
ranged one above the other in a horizontal manner, like 
the leaves of a book, the lowest being the oldest. In conse- 
quence of the commotions which the crust of the globe 
has undergone, many points of its surface have been eleva- 
ted to great heights, in the form of mountains ; and hence 
it is that fossils are sometimes found at the summit of the 
highest mountains, though the rocks containing them were 
originally formed at the bottom of the sea. But even when 
folded, or partly broken, their relative age may still be 
determined by an examination of the ends of the upturned 
strata, where they appear or crop out in succession, at the 
surface, or on the slopes of mountains, as seen in the dia- 
gram (Fig. 154). 

460. The sedimentary rocks are the only ones which 
have been found to contain animal and vegetable remains. 
They are found imbedded in the sediment, just as we 
should find them in the mud now deposited at the bottom of 
the sea, if laid dry. The strata containing fossils are nume- 
rous. The comparison and detailed study of them belongs 

* Underneath the deepest strata containing fossils, between these and the 
Plutonic rocks, are generally found very extensive layers of slates without 
fossils (gneiss, mica-slate, talcose-slate), though stratified, and known to 
the geologist under the name of Metamorphic Rocks (Fig. 154, M), being 
probably sedimentary rocks which have undergone considerable changes. 
The Plutonic rocks, as well as the metamorphic rocks, are not always con- 
fined to the lower levels, but they are often seen rising to considerable 
heights, and forming many of the loftiest peaks of the globe. The former 
also penetrate, in many cases, like veins, through the whole mass of the 
stratified and metamorphic layers, and expand at the surface ; as is the case 
with the trap dykes, and as lava streams actually do now (Fig. 154, T,L). 



to Geology, of which it forms an essential part. A group of 
strata extending over a certain geographical extent, all of 
which contain some fossils in common, no matter what may be 
the chemical character of the rock, whether it be limestone, 
sand or clay, is termed a geological Formation. Thus, the 
coal beds, with the intervening slates and grts, and the 
masses of limestone in which they are often imbedded, 
constitute but one formation, the carboniferous formation. 

461. Among the stratified rocks we distinguish ten prin- 
cipal Formations, each of which indicates an entirely new 
era in the earth's history ; while each of the layers which 
compose a formation indicates but some partial revolution. 
Proceeding from below upwards, they are as follows, as in- 
dicated in the cut, and also in the lower diagram on the 

Fig. 154. 

1st. The Lower Silurian. This is a most extensive 
formation, no less than eight stages of which have been 
made out by Geologists in North America, composed of 
various limestones and sandstones.* 

* 1. Potsdam Sandstone; 2. Calciferous Sandstone; 3. Chrzy Lime- 
stone; 4. Bird's-eye Limestone ; 5. Black River Limestone ; 6. Trentoii 
Limestone; 7. Utica Slate ; 8. Hudson River Group ; being all found in 
the western parts of the United States. 



2d. The Upper Silurian. It is also a veiy extensive 
formation, since about ten stages of it are found in the 
State of New York.* 

3d. The Devonian, including in North America no less 
than eleven stages. t It occurs also in Russia and Scotland, 
where it was first made out as a peculiar formation. 

4th. The Carboniferous Formation, consisting of three 
grand divisions. | 

5th. The Trias, or Saliferous Formation which, contain- 
ing the richest deposits of Salt on the continent of Europe, 
comprises three stages,^ to one of which the Sandstone of 
the Connecticut valley belongs. 

6th. The Oolitic Formation, only faint traces of which 
exist on the continent of America. It comprises at least four 
distinct stages. || 

7th. The Cretaceous or Chalk Formation, of which three 
principal stages have been recognized, two of which are 
feebly represented in this country, in the Southern and Mid- 
dle States. 

8th. The Loiver Tertiary or Eocene, very abundant in the 
Southern States of the Union, and to which belong the 
coarse limestone of Paris, and the London clay in England. 

* 1. Oneida Conglomerate ; 2. Medina Sandstone ; 3. Clinton Group ; 
4. Niagara Group ; 5. Onondaga Salt Group ; 6. Water Limestone ; 
7. Pentamerus Limestone ; 8. Delthyris Shaly Limestone ; 9. Encrinal 
Limestone ; 10. Upper Pentamerus Limestone. 

t 1. Oriskany Sandstone; 2. Cauda-Galli Grit; 3. Onondaga Lime- 
stone; 4. Corniferous Limestone; 5. Marcellus Shale; 6. Hamilton 
Group; 7. Tully Limestone; 8. Genesee Slate; 9. Portage Group; 
10. Chemung Group ; 11. Old Red Sandstone. 

I I. The Permian, extensively developed in Russia, especially in the 
government of Perm; 2. The coal measures, containing the rich deposits 
of coal in the Old and New World ; 3. The Magnesian Limestone of 

1. New Red Sandstone ; 2. Muschelkalk ; 3. Keuper. 

II 1. The Lias; 2. The Lower Oolite ; 3. The Middle Oolite ; 4. The 
Upper Oolite. 


9th. The Upper Tertiary or Miocene , and Pleiocene, 
found also in the United States, as far north as Martha's 
Vineyard, and very extensive in Southern Europe, as well 
as in South America. 

10th. The Drift, forming the most superficial deposits, 
and extending over a large portion of the northern coun- 
tries in both hemispheres. 

We have thus more than forty distinct layers already 
made out, each of which marks a distinct epoch in the 
earth's history, indicating a more or less extensive and 
important change in the condition of its surface. 

462. All the formations are not always found, or are not 
developed to the same extent, in all places. It is the same 
with the several strata of which they are composed. In 
other words, the layers of the earth's crust are not continuous 
throughout, like the coats of an onion. There is no place on 
the globe where, if it were possible to bore down to its 
centre, all the strata would be found. It is easy to under- 
stand how this must be so. Since irregularities in the 
distribution of water upon the hard crust have, necessarily, 
always existed to a certain extent, portions of the earth's 
surface must have been left dry at every epoch of its 
history, gradually forming large continents and islands, as 
the changes were multiplied. And since the rocks were 
formed by the subsidence of sediment in water, no rocks 
would be formed except in regions then covered by water; 
they would be thickest at the parts where most sediment 
was deposited, and gradually thin out towards their circum- 
ference. We may therefore infer, that all those portions of 
the earth's surface which are destitute of a certain formation 
were dry land, during that epoch of the earth's history to 
which such formation relates, excepting, indeed, where 
the rocks have been subsequently removed by the denuding 
action of water or other causes. 


463. Each formation represents an immense period of 
time, during which the earth was inhabited by successive 
races of animals and plants, whose remains are often found, 
in their natural position, in the places where they lived and 
died, not scattered at random, though sometimes mixed to- 
gether by currents of water, or other influences, subsequent 
to the time of their interment. From the manner in which 
the remains of various species are found associated in the 
rock, it is easy to determine whether the animals to which 
these remains belonged lived in the water, or on land, on the 
beach or in the depths of the ocean, in a warm or in a cold 
climate. They will be found associated in just the same 
way as animals that live under similar influences at the 
present day. 

464. In most geological formations, the number of spe- 
cies of animals and plants found in any locality of given 
extent, is not below that of the species now living in an 
area of equal extent ; for though, in some deposits, the vari- 
ety of the animals contained may be less, in others it is 
greater than that on the present surface. Thus, the coarse 
limestone in the neighborhood of Paris, which is only one 
stage of the lower tertiary, contains not less than 1200 spe- 
cies of shells ; whereas the species now living in the Mediter- 
ranean do not amount to half that number. Similar relations 
may be pointed out in America. Mr. Hall, one of the geolo- 
gists of the New York Survey, has described, from the Tren- 
ton limestone (one of the ten stages of the lower Silurian), 170 
species of shells, a number almost equal to that of all the 
species found actually living on the coast of Massachusetts. 

465. Nor was the number of individuals less than at 
present. Whole rocks are entirely formed of animal re- 
mains, particularly by corals and shells. So, also, coal is 
composed of the remains of plants. If we consider the slow- 
ness with which corals and shells are formed, it will give us 


some faint notion of the vast series of ages that must have 
elapsed in order to allow the formation of those rocks, and 
their regular deposition, under the water, to so great a thick- 
ness. If, as all things combine to prove, this deposition took 
place in a slow and gradual manner in each formation, we 
must conclude, that the successive species of animals found 
in them followed each other at long intervals, and are not 
the work of a single epoch. 

466. It was once believed that animals were successively 
created in the order of their relative perfection ; so that 
the most ancient formations contained only animals of the 
lowest grade, such as the Polyps, the Echincderms, to 
which succeeded the Mollusks, then the Articulated Ani- 
mals, and last of all, the Vertebrates. This theory, how- 
ever, is now untenable ; since fossils belonging to each of 
the four departments have been found in the fossiliferous de- 
posits of every age. Indeed, we shall see that even in the 
lower Silurian formation there exist not only Polyps and other 
Radiata, but also numerous Mollusks, Trilobites (belonging 
to the Articulata), and even Fishes. 



467. Each formation, as has been before stated (460), 
contains remains peculiar to itself, which do not extend 
into the neighboring deposits above or below it. Still there 
is a connection between the different formations, more strong 
in proportion to their proximity to each other. Thus, the 
animal remains of the chalk, while they differ from those of 
all other formations, are nevertheless much more nearly re- 
lated to those of the oolitic formation, which immediately 


precedes, than to those of the carboniferous formation, which 
is much more ancient ; and in the same manner, the fossils 
of the carboniferous group approach more nearly to those of 
the Silurian formation, than to those of the Tertiary. 

468. These relations could not escape the observation of 
naturalists, and indeed they are of great importance for 
the true understanding of the development of life at the sur- 
face of our earth. And, as in the history of man, several 
grand periods have been established, under the name of 
Ages, marked by peculiarities in his social and intellectual 
condition, and illustrated by cotemporaneous monuments, 
so, in the history of the earth also, are distinguished several 
great periods, which may be designated as the various Ages 
of Nature, illustrated in like manner by their monuments, 
the fossil remains, which, by certain general traits stamped 
upon them, clearly indicate the eras to which they belong. 

469. We distinguish four Ages of Nature, corresponding 
to the great geological divisions, namely : 

1st. The Primary or Paleozoic Age, comprising the lower 
Silurian, the upper Silurian, and the Devonian. During this 
age there were no air-breathing animals. The fishes were 
the masters of creation. We may therefore call it the Reign 
of Fishes. 

2d. The Secondary Age, comprising the carboniferous 
formation, the Trias, the oolitic, and the cretaceous forma- 
tions. This is the epoch in which air-breathing animals first 
appear. The reptiles predominate over the other classes, 
and we may therefore call it the Reign of Reptiles. 

3d. The Tertiary Age, comprising the tertiary formations. 
During this age, terrestrial mammals, of great size, abound. 
This is the Reign of Mammals. 

4th. The Modern Age, characterized by the appearance 
of the most perfect of all created beings. This is the Reign 
of Man. 



Let us review each of these four Ages of Nature, with re- 
ference to the diagram at the beginning of the volume. 

470. THE PALEOZOIC AGE. Reign of Fishes. The 
paleozoic fauna, being the most remote from the present 
epoch, presents the least resemblance to the animals now 
existing, as will easily be perceived by a glance at the fol- 

Fig. 155. 

lowing sketches (Fig. 155). In no other case do we meet 
with animals of such extraordinary shapes, as in the strata 
of the Paleozoic age. 

471. We have already stated (466) that there are found, 
in each formation of the primary age, animal remains of all 
the four great departments, namely, vertebrates, articulata, 
mollusks, and radiata. We have now to examine to what 
peculiar classes and families of each department these re- 
mains belong, with a view to ascertain if any relation 


between the structure of an animal, and the epoch of its first 
appearance on the earth's surface may be traced. 

472. As a general result of the inquiries hitherto made, it 
may be stated that the paleozoic animals belong, for the 
most part, to the lower divisions of the different classes. 
Thus, of the class of Echinoderms, we find scarcely any 
but Crinoids, which are the least perfect of the class. We 
have represented, in the above sketches, several of the most 
curious forms,* as well as of the Polyps, of which there are 
some quite peculiar types from the Trenton limestone and 
from the Black River limestone. 

473. Of the Mollusks, the bivalves or Acephala are nu- 
merous, but for the most part belong to the Brachiopoda, 
that is to say, to the lowest division of the class, including 
mollusks with unequal valves having peculiar appendages 
in the interior. The Leptcena alternata (b) which is found 
very abundantly in the Trenton limestone is one of these 
shells. The only fossils yet found in the Potsdam sandstone, 
the oldest of all fossiliferous deposits, belong also to this 
family (Lingula prima, a). Besides this, there are also 
found some bivalves of a less uncommon shape (Avicula 
decussata, e). 

474. The Gasteropods are less abundant ; some of them 
are of a peculiar shape and structure (Bucania expansa,/; 
Euomphalus hemisphcericus, c). Those more similar to 
our common marine snails have all an entire aperture ; 
those with a canal being of a more recent epoch. 

475. Of the Cephalopods we find some genera not less 
curious, part of which disappear in the succeeding epochs ; 

* (i) Cyathocrinus ornatissimus, Hall ; (j) Melocrinus Amphora, Goldf. 
(k) Cariocrinus ornatus, Say; (/) Columnaria alveolatv ; (m) Cyatho- 
phyllum quadrigeminum, Goldf.; (n, o) Caninia Jlexuosa ; (p) Cheetetes 



such, in particular, as those of the straight, chambered shells 
called Orthoceratites, some of which are twelve feet in 
length (Orthoceras fusiforme, g). There are also found 
some of a coiled shape, like the Ammonites of the secondary 
age, but having less complicated partitions ( Trocholites 
ammonius, d). The true cuttle-fishes, which are the highest 
of the class, are not yet found. On the contrary, the Bryo- 
zoa, which have long been considered as polyps, but which, 
according to all appearances, are mollusks of a very low 
order, are veiy numerous in this epoch. 

476. The Articulata of the Paleozoic age are mostly 
Trilobites, animals which evidently belong to the lower 
order of the Crustaceans (Fig. 156). There is an incom- 
pleteness and want of development, in the form of their 
body, that strongly reminds us of the embryo among the 
crabs. A great many genera have already been discovered. 


d ^KYVV^^S-^ " I %3P e 

Fig. 156. 

We may consider as belonging to the more extraordinary, 
the forms here represented, (Harpes, a ; Arges, 1) ; Brontes, 
c ; and Platynotus, d] ; the latter, as well as the Isotelus, 
the largest of all, being peculiar to the Paleozoic deposit of 
this country. Some others seem more allied to the crusta- 
ceans of the following ages, but are nevertheless of a very 
extraordinary form, as Eurypterus remipes (e). There 
are also found, in the Devonian, some very large Ento- 
mostraca. The class of Worms is represented only by a 




few Serpulae, which are marine worms, surrounded by a 
solid sheath. The class of Insects is entirely wanting. 

477. The inferiority of the earliest inhabitants of our 
earth appears most striking among the Vertebrates. There 
are as yet neither reptiles, birds, nor mammals. The fishes, 
as we have said, are the sole representatives of this division 
of animals. 

478. But the fishes of that early period were not like 
ours. Some of them had the most extraordinary forms, so 
that they have been often mistaken for quite different ani- 
mals ; for example, the Pterichthys (a), with its two wing- 


Fig. 157. 

like appendages, and also the Coccosteus (&) of the same de- 
posit, with its large plates covering the head and the ante- 
rior part of the body. There are also found remains of 
shark's spines (e), as well as palatal bones (rf), the latter of a 
very peculiar kind. Even those fishes which have a more 
regular shape, as the Dipterus (c), have not horny scales 
like our common fishes, but are protected by a coat of bony 
plates, covered with enamel, like the gar-pikes of the 
American rivers. Moreover, they all exhibit certain char- 
acteristic features, which are very interesting in a physio- 
logical point of view. They all have a broad head, and a 
tail terminating in two unequal lobes. What is still more 
curious, the best preserved specimens show no indications 


of the bodies of vertebrae, but merely the spinous processes ; 
from which it must be infered that the body of the vertebra 
was cartilaginous, as it is in our Sturgeons. 

479. Recuring to what has been stated on that point, 
in Chapter Twelfth, we thence conclude, that these ancient 
fishes were not so fully developed as most of our fishes, 
being, like the Sturgeon, arrested, as it were, in their devel- 
opment ; since we have shown that the Sturgeon, in its or- 
ganization, agrees, in many respects, with the Cod or 
Salmon in their early age. 

480. Finally, there was, during the Paleozoic age, less 
variety among the animals of the different regions of the 
globe ; and this may be readily explained by the peculiar 
configuration of the earth at that epoch. Great mountains 
did not then exist ; there were neither lofty elevations nor 
deep depressions. The sea covered the greater part, if not 
the whole, of the surface of the globe ; and the animals 
which then existed, and whose remains have been preserved, 
were all, without exception, aquatic animals, breathing by 
gills. This uniform distribution of the waters impressed a 
very uniform character upon the whole Animal Kingdom. 
Between the different zones and continents, no such strange 
contrasts of the different types existed as at the present 
epoch. The same genera, and often the same species were 
found in the seas of America, Europe, Asia, Africa, and 
New Holland ; from whence we must conclude that the 
climate was much more uniform than at the present day. 
Among the aquatic population, no sound was heard. All 
creation was then silent. 

481. THE SECONDARY AGE. Reign of Reptiles. The 
Secondary age displays a greater variety of animals as well 
as plants. The fantastic forms of the Paleozoic age disap- 
pear, and in their place we see a greater symmetry of 
shape. The advance is particularly marked in the series of 


vertebrates. The fishes are no longer the sole representa- 
tives of that department. Reptiles, Birds, and Mammals 
successively make their appearance, but the Reptiles are 
preponderant, particularly in the oolitic formation ; on which 
account we have called this the Reign of Reptiles. 

482. The carboniferous formation is the most ancient of 
the Secondary age. Its fauna shows, in various respects, a 
great analogy with that of the Paleozoic epoch, especially 
in its Tribolites and Mollusks.* Besides these, we meet 
here with the first air-breathing animals, which are Insects 
and Scorpions. At the same time, land-plants first make 
their appearance, namely, ferns of great size, club-mosses, 
and other fossil plants. This corroborates what has been 
already said concerning the intimate connection that exists, 
and from all times has existed, between animals and the 
land-plants (399). The class of Crustaceans has also im- 
proved during the epoch of the coal. It is no longer com- 
posed exclusively of Trilobites, but the horse-shoe crabs also 
appear, with other gigantic forms. Some of the Mollusks 
seem also to approach those of the Oolitic period, particu- 
larly the Bivalves. 

483. In the Trias period, which immediately succeeds 
the Carboniferous, the fauna of the Secondary age acquires 
its definitive character ; here the Reptiles first appear. 
They are huge Crocodilian animals, belonging to a pecu- 
liar order, the Rhizodonts (Protosaurus, Notosaurus, and 
Labyrintliodori). The well-known discoveries of Professor 

* This circumstance, in connection with the absence of Reptiles, has 
caused the coal-measures to be generally referred to the Paleozoic epoch. 
But there are other reasons which induce us to unite the carboniferous 
period with the secondary age, especially when considering that here the 
land animals first appear, whereas, in the Paleozoic age, there are only 
marine animals, breathing by gills ; and also, that a luxuriant terrestrial 
vegetation was developed at that epoch. 



Hitchcock, in the red sandstone of the Connecticut, have 
made us acquainted with a great number of birds' tracks 

a Fig. 158. b c 

(Fig. 157, #, &), belonging to this epoch, for the most part in- 
dicating birds of gigantic size. These impressions, which he 
has designated under the name of Ornithichnites, are some 
of them eighteen inches in length, and five feet apart, far 
exceeding in size the tracks of the largest ostrich. Other 
tracks, of a very peculiar shape, have been found in the red 
sandstone of Germany and in Pennsylvania. They were 
probably made by Reptiles, which have been called Chei- 
rotherium, from the resemblance of the track to a hand (c). 
The Mollusks, Articulates, and Radiates of this period, 
approach to the fauna of the succeeding period. 

484. The fauna of the Oolitic formation is remarkable for 
the great number of gigantic Reptiles which it contains. In 


this formation we find those enormous Amphibia, known 
under the name Ichthyosaurus, Plesiosaurus, Megalosaurus, 
and Iguanodon. The first, in particular, the Icthyosaurus 
(Fig. 159, a), greatly abounded on the coast of the conti- 
nents of that period, and their skeletons are so well pre- 
served, that we are enabled to study even the minutest 
details of their structure, which differs essentially from that 
of the Reptiles of the present day. In some respects they 
form an intermediate link between the Fishes and Mammals, 


and may be considered as the prototypes of the Whales, hav- 
ing, like them, limbs in the form of oars. The Plesiosaurus 
, agrees, in many respects, with the Ichthyosaurus, in its 

structure, but is easily distin- 
guished by its long neck, which 
resembles somewhat the neck of 
some of our birds. A still more 
extraordinary Reptile is the 
Pterodactylus (Fig. 160), with 
its long fingers, like those of 
Fig. 160. a bat, and which is thought 

to have been capable of flying. 

485. It is also in the upper stages of this formation that 
we first meet with Tortoises. Here also we find impres- 
sions of several families of insects, (Libellulce, Coleoptera, 
Ichneumons, <^c.) Finally, in these same stages, the slates 
of Stonesfield, the first traces of Mammals are found, 
namely, the jaws and teeth of animals having some re- 
semblance to the Opossum. 

486. The department of Mollusks is largely represented 
in all its classes. The peculiar forms of the primary age 
have almost all disappeared, and are replaced by a much 
larger quantity of new forms. Of the Brachiopods only one 


Fig. 161. 

type is very abundant, namely, that of the Terebratula 
(Fig. 161, a). Among the other Bivalves there are many 
peculiar forms, as the Goniomya (Z>), and the Trigonia (c). 
The Gasteropods display a great variety of species, and also 
the Cephalopods, among which the Ammonites are the 



most prominent (d). There are also found, for the first 
time, numerous repre- 
sentatives of the Cut- 
tle-fishes, under the 
form of Belemnites 
(Fig. 162), an extinct 
type of animals, sur- Fig. 162. 6 

rounded by a sheath, and containing in their interior a 
peculiar bone, somewhat similar to the bone of the Sepia, 
and which commonly is the only preserved part (J). 

487. The variety is not less remarkable among the 
Radiates. There are to be found representatives of all the 
classes ; even traces of Jelly-fishes have been made out in 
the slate of Solenhofen, in Bavaria. The Polyps were 
very abundant at that epoch, especially in the upper stages, 
one of which has received the name of Coral-rag. Indeed, 
there are to be found whole reefs of corals in their natural 
position, similar to those which are to be seen in the islands 


Fis:. 163. 

of the Pacific. Among the most remarkable types of stony 
Polyps, may be named the fan-like Lobophyllia (L.flabel- 
lum, a), and various forms of tree-corals (Lithodendron 
2iseudostylina, b). But the greatest variety exists among the 
Echinoderms. The Crinoids are not quite so numerous as 
in former ages. Among the most abundant are the Pent.a- 
crlnus (c). There are also already found Comatula-like 
animals, that is to say, free Crinoids, (Pterocoma pinnata, d). 



Many Star-fishes are likewise to be found in the various 
stages of this formation. Finally, there is an extraordinary 
variety of Echini, among them Cidaris (e), with large spines, 
and several other types not found before, as, for example, 
the Disaster (/) and the Nudeolites (g). 

488. The fauna of the Cretaceous period bears the 
same general characters as the Oolitic, but with a more 
marked tendency towards the actual forms. Thus the 
Ichthyosauri and Plesiosauri, that characterize the pre- 
ceding epoch, are succeeded by gigantic Lizards, more 
nearly approaching the Reptiles of the present day. Among 
the Mollusks, a great number of new forms appear, espe- 
cially among the Cephalopods,* some of which resemble 



c Fig. 164. e 

the Gasteropods in their shape, but are nevertheless 
chambered. The Ammonites themselves are quite as 

b Fig. 165." 

numerous as in the Oolitic period, and are in general 
much ornamented (a). The Acephala furnish us also 
with peculiar types, not found elsewhere, Ma gas (), 

* (a) Ammonites; (b) Crioceras ; (c) Scaphites ; (d) Ancyloceras ; 
(e) Hamites; (/) Baculites ; () Turrilites, 



the Jnoceramus (5), the Hippurites (c), and peculiar Spon- 
dyli, with long spines (d). There is also a great variety of 
Gasteropods, among which are some peculiar forms of Pleu- 

b c d e 


Fig. 1 66. 

rotomaria (e). The Radiates are not inferior to the others 
in variety.* 

489. TERTIARY AGE. Reign of Mammals. The most 
significant characteristic of the Tertiary faunas is their 
great resemblance to those of the present epoch. The ani- 
mals belong in general to the same families, and mostly to the 
same genera, differing only as to the species. And the spe- 
cific differences are sometimes so slightly marked, that a 
considerable familiarity with the subject is required, in order 
readily to detect them. Many of the most abundant 
types of former epochs have now disappeared. The 
changes are especially striking among the Mollusks, the 
two great families of Ammonites and Belemnites, which 
present such an astonishing variety in the Oolitic and Creta- 
ceous epochs, being now completely wanting. Changes of 
no less importance take place among the Fishes, which are 
for the most part covered with horny scales, like those of 
the actual epoch, while in earlier ages they were generally 
covered with enamel. Among the Radiata, we see the 
family of Crinoids reduced to a very few species, while, on 
the other hand, a great number of new Star-fishes and Sea- 
urchins make their appearance. There are besides, innu- 
merable remains of a very peculiar type of animals, almost 

* (a) Diploctenium cordalum ; (b) Marsupites ; (c) Salenia ; (d) Gale- 
rites : (e) Micraster cor-anguinum. 



unknown to the former ages, as well as to the actual period. 
They are little-chambered shells, known to 
geologists under the name of Nummulites, 
from their coin-like appearance, and form very 
extensive layers of rocks (Fig. 167). 

Fig. 167. 

490. But what is more important, in a philosophical point 
of view, is, that the aquatic animals are no longer predomi- 
nant in the Creation. The great marine or amphibian 
reptiles give place to numerous mammals of great size. 
For which reason we have called this age the Reign of 
Mammals. Here are also found the first distinct remains 
of fresh- water animals. 

491. The lower stage of this formation is particularly 
characterized by great Pachyderms, among which we may 
mention the Paleotherium and Anoplotherium, which have 
acquired such celebrity from the researches of Cuvier. 
These animals, among others, abound in the Tertiary form- 
ations of the neighborhood of Paris. The Paleotheriums, of 

Fig. 168. Fig. 169. 

which several species are known, are the most common ; 
they resemble (Fig. 168), in some respects, the Tapirs, 
while the Anoplotheriums are more slender animals (Fig. 
169). On this continent are found the remains of a most ex- 
traordinary animal of gigantic size, the Basilosaurus, a true 
cetacean. Finally, in these stages, the earliest remains of 
Monkeys have been detected. 
492. The fauna of the upper stage of the Tertiary forma- 


tion approaches yet more nearly to that of the present 
epoch. Besides the Pachyderms, that were also predomi- 
nant in the lower stage, we find numbers of carnivorous 
animals, some of them much surpassing in size the lions 
and tigers of our day. We meet also gigantic Edentata, 
and Rodents of great size. 

493. The distribution of the Tertiary fossils also reveals 
to us the important fact, that in this epoch, animals of the 
same species were circumscribed in much narrower limits 
than before. The earth's surface, highly diversified by 
mountains and valleys, was divided into numerous basins, 
which, like the Gulf of Mexico, or the Mediterranean of this 
day, contained species not found elsewhere. Such was the 
basin of Paris, that of London, and on this continent, that of 
South Carolina. 

494. In this limitation of some types within certain bounds, 
we distinctly observe another approach to the actual con- 
dition of things, in the fact that certain groups of animals 
which occur only in particular regions are found to have 
already existed in the same regions during the Tertiary 
epoch. Thus the Edentata are the predominant animals 
in the fossil fauna of Brazil as well as in its actual fauna ; 
and Marsupials were formerly as numerous in New Hol- 
land as they now are, though in general of much larger size. 

495. THE MODERN EPOCH. Reign of Man. The 
Present epoch succeeds to, but is not a continuation of, the 
Tertiary age. These two epochs are separated by a great 
geological event, traces of which we see everywhere around 
us. The climate of the northern hemisphere, which had 
been, during the Tertiary epoch, considerably warmer than 
now, so as to allow of the growth of palm-trees in the tem- 
perate zone of our time, became much colder at the end of 
this period, causing the polar glaciers to advance south, much 
beyond their previous limits. It was this ice, either floating 


like icebergs, or, as there is still more reason to believe, 
moving along the ground, like the glaciers of the present 
day, that, in its movement towards the South, rounded and 
polished the hardest rocks, and deposited the numerous 
detached fragments brought from distant localities, which 
we find everywhere scattered about upon the soil, and 
which are known under the name of erratics, boulders, or 
greyheads. This phase of the earth's history has been 
called, by geologists, the Glacial or Drift period. 

496. After the ice that carried the erratics had melted 
away, the surface of North America and the North of Europe 
was covered by the sea, in consequence of the general 
subsidence of the continents. It is not until this period 
that we find, in the deposits known as the diluvial or pleis- 
tocene formation, incontestable traces of the species of ani- 
mals now living. 

497. It seems, from the latest researches of Geologists, 
that the animals belonging to this period are exclusively 
marine ; for, as the northern part of both continents was 
covered to a great depth with water, and only the summits 
of the mountains were elevated above it, as islands, there 
was no place in our latitudes where land or fresh-water 
animals could exist. They appeared therefore at a later 
period, after the water had again retreated ; and, as from 
the nature of their organization, it is impossible that they 
should have migrated from other countries, we must con- 
clude that they were created at a more recent period than 
our marine animals. 

498. Among these land animals which then made their 
appearance, there were representatives of all the genera 
and species now living around us, and besides these, many 
types now extinct, some of them of a gigantic size, such as 
the Mastodon, the remains of which are found in the upper- 
most strata of the earth's surface, and probably the very 



last large animal which became extinct before the creation 
of man.* 

Fig. 170. 

499. It is necessary therefore, to distinguish two periods 
in the history of the animals now living ; one in which the 
marine animals were created, and a second, during which 
the land and fresh-water animals made their appearance, 
and at their head MAN.! 


500. From the above sketch it is evident that there is a 
manifest progress in the succession of beings on the surface 

* The above diagram is a likeness of the splendid specimen disin- 
tered at Newburg, N. Y"., now in the possession of Dr. J. C. Warren, 
in Boston ; the most complete skeleton which has ever been discovered. 
It stands nearly twelve feet in height, the tusks are fourteen feet in length) 
and nearly every bone is present, in a state of preservation truly wonderful. 

t The former of these phases is indicated in the frontispiece, by a nar- 
row circle, inserted between the upper stage of the Tertiary formation and 
the Reign of Man properly so called. 


of the earth. This progress consists in an increasing simi- 
larity to the living fauna, and among the Vertebrates, espe- 
cially, in their increasing resemblance to Man. 

501. But this connection is not the consequence of a 
direct lineage between the faunas of different ages. There 
is nothing like parental descent connecting them. The 
Fishes of the Paleozoic age are in no respect the ancestors 
of the Reptiles of the Secondary age, nor does Man descend 
from the Mammals which preceded him in the Tertiary age. 
The link by which they are connected is of a higher 
and immaterial nature ; and their connection is to be sought 
in the view of the Creator himself, whose aim, in forming 
the earth, in allowing it to undergo the successive changes 
which Geology has pointed out, and in creating successively 
all the different types of animals which have passed away, 
was to introduce Man upon the surface of our globe. 
Man is the end towards which all the animal creation 
has tended, from the first appearance of the first Paleozoic 

502. In the beginning His plan was formed, and from it 
He has never swerved in any particular. The same Being 
who, in view of man's moral wants, provided and declared, 
thousands of years in advance, that " the seed of the woman 
shall bruise the serpent's head," laid up also for him in the 
bowels of the earth, those vast stores of granite, marble, 
coal, salt, and the various metals, the products of its several 
revolutions ; and thus was an inexhaustible provision made 
for his necessities, and for the development of his genius, 
ages in anticipation of his appearance. 

503. To study, in this view, the succession of animals in 
time, and their distribution in space, is therefore to become 
acquainted with the ideas of God himself. Now, if the suc- 
cession of created beings on the surface of the globe is the 
realization of an infinitely wise plan, it follows that there 


must be a necessary relation between the races of ani- 
mals, and the epoch at which they appear. It is necessary, 
therefore, in order to comprehend Creation, that we com- 
bine the study of extinct species with that of those now 
living, since one is the natural complement of the other. A 
system of Zoology will consequently be true, in proportion 
as it corresponds with the order of succession among 



Abdomen, the lower cavity of the 
body, 17. 

Abranclaates, without gills, xvii. 

Acalepha, a class of Radiates many 
species of which produce tingling 
when handled. 

Acephala, mollusks having no dis- 
tinct head, like clams, xix. 

Acoustic, pertaining to the sense of 
hearing, 32. 

Actinia, digestive apparatus of, 73. 

Affinity, relationship, 6, 63. 

Ages of Nature, 189. 

Albumen, the white of egg, 108. 

Alimentary canal, 73. 

Alimentation, the process of nutri- 
tion, 18. 

Allantois, Allantoidian, 119. 

Alligator, teeth of, 80. 

Alternate reproduction, 127 ; conse- 
quences of, 136 ; difference be- 
tween, and metamorphosis, 137. 

Amblyopsis spelaeus, 31. 

Ammonites, xvii. 198, 200, 201. 

Amnios, 120. 

Amphibia, 71. 

Amphipods, a family of crustaceans. 

Amphioxus, its place, 148. 

Amphiuma, 177. 

Analogy, 6. 

Anatifa, metamorphoses of, 145. 

Ancyloceras, 200. 

Animalcule, a minute animal, xix. 

Animal heat, 96. 

Animal life, 20 ; organs of, 20. 

Animals, number of, 3. 

Animals and plants, differences be- 
tween, 17. 


Animate, possessed of conscious- 
ness, 19. 

Anoplotherium, 202. 

Antenna, the jointed feelers of lob- 
sters, insects, &c., 53. 

Aorta, the great blood-vessel arising 
from the heart, 90. 

Aphides, reproduction of, 131. 

Apophysis, a projection from the 
body of a bone, 149. 

Apparatus of motion, 48. 

Aptera, wingless insects, xvii. 

Aquatic, living in water. 

Aqueous, like water. 

Aqueous humor, 126. 

Arctic fauna, 164. 

Areolar tissue, 14. 

Arges, 193. 

Aristotle's lantern, 77. 

Arm, different forms of, 59. 

Artery, 90. 

Articulates, composed of joints, like 
the lobster or caterpillar ; number 
of, 3. 

Ascidia, bottle-shaped mollusks with- 
out a shell. 

Assimilation, the change of blood in- 
to bone, muscle, &c. 96. 

Astacus pellucidus, 31. 

Asteridee, the family of star-fishes, 

Auditory, pertaining to the sense of 
hearing, 32. 

Auricle, a cavity of the heart, like a 
little ear, 89. 

Avicula decussata, 192. 

Axolotl, 177. 



Baculites, 200. 

Balanus, the barnacle, 144. 

Basilosaurus, 202. 

BatrachianSj the frog tribe, xvi. 

Beak, 79. 

Belemnites, 199, 201. 

Bird-tracks, in red sandstone, 197. 

Birds, number of, 3. 

Bivalve, having two shells, like the 

clam, 3. 
Blastoderm, the embryonic germ, 


Blind-fishes, 31. 
Blood, 86. 
Boulders, 204. 
Brachiopods, a class of mollusks, 

Brain, 21. 
Branchiae, gills, 94. 
Branchifers, univalve mollusks 

breathing by gills, xviii. 
Bronchi, tubes brandling from the 

windpipe in the lungs, 93. 
Brontes, 193. 
Bryozoa, xviii. 193. 
Bucania expansa, 192. 

Calcareous, composed of lime, 51, 

Campanularia, reproduction of, 134, 


Canine teeth, 81. 
Caninia flexuosa, 192. 
Canker-worm, metamorphoses of, 


Cannon-bone, 60. 
Capillary vessels, 88. 
Carapace, the upper covering of the 

crab or tortoise, 51. 
Carbon, the basis of charcoal and 

most combustibles, 17. 
Carboniferous rocks, 186, 196. 
Cariocrinus ornatus, 192. 
Carnivora, animals feeding on flesh, 

xvi. ; teeth of, 82. 
Carpus, the wrist, 59. 
Cartilage, gristle, 15. 
Cartilaginous tissue, 14. 
Cell, 13 ; nucleated, 14. 
Cephalopods, mollusks with arms 

surrounding the head, like the 

cuttle-fish, xvii. 

Cercaria, reproduction of, 129, 138. 
Cerebral, pertaining to the brain, 21. 
Cestracion Philippi, 171. 
Cetaceans, marine animals which 

nurse their young, like the whale, 

porpoise, &c. xvi. 

Chaetetes lycoperdon, 102. 

Chalaza, the albuminous thread by 
which the yolk of the egg is sus- 
pended, 109. 

Chambers of the eye, 26. 

Cheirotherium, 197. 

Chelonians, reptiles of the tortoise 
tribe, xvi. 

Chorion, 120. 

Choroid, coat of the eye, 25. 

Chrysalis, the insect in its passage 
from the worm to the fly state, 

Chyle, 74. 

Chyme, 75. 

Cilia, microscopic hairs, like eye- 
lashes, 57, 84, 87, 94. 

Circulation, 86 ; great, 90 ; pulmo- 
nary or lesser, 90 ; complete, 90 ; 
incomplete, 91. 

Cirrhipedes, Crustacea having curled 
feelers, like the barnacles, fig. 145. 

Clavicle, the collar-bone, 59. 

Climbing, 68. 

Coccosteus, 194. 

Cold-blooded animals, 96. 

Coleopterous, insects with hard 
wing cases, like the dor-bug, 3. 

Collar-bone, 59. 

Columnaria alveolata, 102. 

Comatula, metamorphosis of, 147, 

Constancy of species, 43. 

Cornea, the transparent portion of 
the eye, 25. 

Corpuscles, minute bodies, 15. 

Cossus ligniperda, muscles of, 53. 

Cretaceous, or chalk formation, 186. 

Cricoid, ring-like, 41. 

Crinoid, lily-like star-fishes, xviii. 

Crioceras, 200. 

Crustacea, articulated animals hav- 
ing a crust-like covering, like the 
crab and horse-shoe ; heart of, 91. 

Crypts, little recesses or sacs, 100. 

Crystalline lens, 25. 

Ctenoids, fishes which have the 
edge of the scales toothed, xvi. 

Ctenophori, soft, radiated animals, 
moving by cilia, xix. 

Cuttle-fish, jaws of, 78 ; heart of, 91 ; 
metamorphosis of, 148 ; mode of 
swimming, 71. 

Cyathocrinus ornatissimus, 192. 

Cyathophyllum quadrigeminum, 192. 

Cycloids, fishes with smooth scales, 



Deciduous, not permanent during a 

lifetime, 426. 
Deglutition, the act of swallowing-, 

Dentition, form and arrangement of 

the teeth. 
Department, a primary division of 

the animal kingdom, xiv. 
Development of the white-fish, 115. 
Devonian rocks, 186. 
Diaphragm, the partition between 

the chest and abdomen, 50, 93. 
Diastole, the dilatation of the heart, 


Digestion, 73. 

Diploctenium cordatum, 201. 
Dipterus, 194. 

Disc, a more or less circular, flat- 
tened body, iii. 
Discophori, disc-shaped animals, like 

the jelly-fish, xviii. 
Distoma, reproduction of, 130 ; in 

eye of the perch, 140. 
Distribution of animals in time, 182. 
Dodo, its disappearance, 178. 
Dorsal cord, 113. 
Dorsibranchiates, mollusks having 

gills upon the back, xviii. 
Drift, 187, 204. 

Duck-barnacle. See Anatifa. 
Dysaster, 200. 

Ear, 32. 

Echinoderms, radiate animals armed 
with spines externally, like the 
sea-urchin, xviii. 

Echinus, the sea-urchin xviii ; jaws 
of, 77 ; heart of, 91 ; mode of pro- 
gression, 57. 

Echinus sanguinolentus, metamor- 
phosis of, 146. 

Egg, 102 ; form of, 103 ; formation 
of, 104 ; ovarian, 104 ; laying of, 
105 ; composition of, 107 ; devel- 
opment of, 109 ; of Infusoria, 141. 

Elementary structure of organized 
bodies, 12. 

Embryo, the young animal before 
birth, 9, 102 ; development of, 109. 

Embryology, 102, 110 ; importance 
of, 122. 

Endosmose, 99. See Exosmose. 

Engeena, a large ourang, 174. 

Entomostraca, xvii. 

Eocene formation, 1S6. 

Ephyra, 133, 138. 

Epidermis, the scarf-skin, 99. 

Equivocal reproduction, 127. 

Erratics, rolling stones, 204. 

Euomphalus heniisphericus, 192. 

Eurypterus remipes, 193. 

Excretions, 101. 

Exhalation, 99. 

Exosmose and Endosmose, the pro- 
cess by winch two fluids pass each 
way, through a membrane which 
separates them, so as to become 
mingled, 99. 

Eye, simple, 27 ; aggregate, 29 ; 
compound, 30 ; destitution of, 31 ; 
compared to a camera obscura, 27. 

Fa^ette, a very small surface, 30. 
Family, a group including several 

genera, xiv. 

Fauna, 154 ; distribution of, 161. 
Femur, the thigh-bone, 63. 
Fibula, the smallest of the two bones 

of the leg, 63. 
Fins, 70. 
Fishes, number of, 3 ; heart of, 91 ; 

reign of, 190, 191. 
Fissiparous reproduction, propaga- 

gation by fissure or division, 125. 
Flight, 68. 

Fluviatile, pertaining to rivers, 3. 
Follicles, minute pouches, 100. 
Formation, geological, 185. 
Fossil, dug from the earth, applied to 

the remains of animals and plants. 
Function, the office which an organ 

is designed to perform, 5. 

Galeopithecus, its facilities for leap- 
ins:, 69, 175. 

Galerites, 201. 

Gallinaceous, birds allied to the do- 
mestic fowl, 161. 

Gallop, 67. 

Ganglions, scattered nervous mas- 
ses, from which nervous threads 
arise, 22. 

Ganoids, fishes having large, bony, 
enamelled scales, mostly fossil, 

Gasteropods, mollusks which crawl 
by a flattened disc, or foot, on the 
under part of the body, like the 
snail, xvii. 

Gastric juice, 75. 

Gavial, a crocodile, with a long, 
slender head. 

Gemmiparous reproduction, propa- 
gation by budding, 125. 

General properties of organized 
bodies, 11. 



Genus, xiv. 

Geographical distribution of ani- 
mals, 154. 

Geological succession of animals, 

Germ, the earliest manifestation of 
the embryo, 18, 111. 

Germinative disc, 111 ; vesicle, 104 ; 
dot, 104, 108. 

Gestation, the period of carrying 
youiiir, 106. 

Gi'lls, 7, 94. 

Glacial period, 204. 

Glands, 100 ; salivary, 100. 

Globules of chyle, 76 ; of blood, 86. 

Glottis, 41. 

Grallatores, birds with long legs for 
wading, xvi. 

Grand-nurses of Cercaria, 131. 

Granivorous, birds feeding on grain. 

Grit, coarse sandstone, 184. 

Hamites, 200. 

Harmony of organs, 82. 

Harpes, 193. 

Hearing, 31. 

Heart, 89. 

Herbivora, animals feeding on grass 
and leaves, xvi. 

Hibernation, torpid state of animals 
during winter, 97. 

Hippurites, 201. 

Holothurians, soft sea-slugs, biche- 
le-mar, xviii. 

Homology, 6. 

Humerus", the shoulder-bone, 69. 

Hyaline matter, pure, like glass, 15. 

Hydra, egg of, 104 ; propagation of, 
125, 127. 

Hydrogen, a gas which is the princi- 
pal constituent of water, 17. 

Hydroids, a family of polyps, xix. 

Ichthyosaurus, 197, 200. 

Icterus Baltimore, nest of, 46. 

Igneous, that have been acted upon 
by fire, 183. 

Iguanodon, 197. 

Inanimate, destitute of conscious- 
ness, 19. 

Incessores, perching birds, like birds 
of prey, xv. 

Incisor teeth, 81. 

Incubation, hatching of eggs by the 
mother, 107. 

Infusoria, microscopic animals in- 
habiting the water, not yet fully 
arranged in their proper classes, 

xix. ; motions of, 16 ; generation 

of, 141. 

Inoceramus, 201. 

Inorganic, not made up of tissues, 11. 
Insalivation, 83. 
Instinct, 45. 
Intelligence, 44. 
Intercellular passages, 13. 
Invertebrates, animals destitute of a 

Iris, the colored portion of the eye, 

Isotelus, 193. 

Jelly-fish. See Medusa. 
Judgment, 44. 

Labyrinthodon, 196. 

Lacertans, animals of the lizard 

tribe, xvi. 
Lacteals, vessels which take up the 

nutriment, 76. 
Lamellibranchiates, mollusks having 

gills arranged in sheets, like the 

clam and oyster, xviii. 
Larva, the caterpillar or worm state 

of an insect. 
Larynx, 41. 

Layers of the embryo, 112. 
Leaping, 67. 
Leptsena alternata, 192. 
Life, 11, 20. 
Limbs, 38. 

Limuea, parasites of, 129 - 31. 
Lingula prima, 192. 
Lithodendron pseudostylina, 199. 
Liver, 101. 

Lobopbyllia flabellum, 199. 
Lobsters, mode of swimming, 70 ; 

nervous system, 22. 
Locomotion, 55 ; organs of, 58 ; 

modes of, 64. 
Lungs, 92. 
Lymphatic vessels, 76. 

Magas, 200. 

Mammals, animals which nurse 
their young, xvi. ; number of, 3 ; 
reign of, 190, 201, 202. 

Man, reign of, 190, 203 ; races of, 
180 ; liis twofold nature, 1. 

Manducata, insects furnished with 
jaws, xvii. 

Marchantia polymorpha, reproduc- 
tion of, 135. 

Marl, earth principally composed of 
decayed shells and corals, 184. 

Marsupials, animals with a pouch 



for carrying their young, as the 
opossum ; gestation of, 151. 

Marsupites, 5201. 

Mastication, 77. 

Mastodon, 204. 

Matrix, the organ in which the em- 
bryo is developed, 121. 

Medulla oblongata, continuation of 
the brain into the back-bone. 

Medusa, jelly-like animals living in 
the sea, xviii. ; development of, 
132 ; digestive organs, 70. 

Megalobatrachus, 177. 

Megalosaurus, 197. 

Melocrinus amphora, 192. 

Memory, 44. 

Menobfanchus, 169, 177. 

Menopdma, 169, 177. 

Merganser, an aquatic bird allied to 
the goose, 42, 161. 

Metacarpus, the wrist, 59. 

Metamorphic rocks, 184. 

Metamorphosis, 119, 142 ; of the silk- 
worm, 143 ; canker-worm, 144 ; 
duck-barnacle, 345; star-fish, 146; 
comatula, 147. 

Micraster cor-anguinum, 201. 

Miocene formation, 187. 

Modern age, 190, 203. 

Molar teeth, 81. 

Molecules, very minute particles, 

Mollusks, soft animals of the snail 
and oyster kind ; heart of, 90 ; 
liver of, 101 ; number of, 3 ; meta- 
morphosis of, 147. 

Monkey, teeth of, 81. 

Morioculus, mode of carrying eggs, 

Moulting, the shedding of feathers, 
hair, &c. 98. 

Muscles, 48 ; disposition of, in in- 
sects, 53 ; in fishes, 54 ; in birds, 

Muscular tissue, 15. 

Myxine glutinosa, its eye, 31. 

Natatores, birds with webbed feet 
for swimming, xvi. 

Natica, tongue of, 78 ; heart of, 91. 

Nautili, xvii. 

Neptunian rocks, 183. 

Nereis, jaws of, 78 ; gills of, 57 ; eye, 

Nervous system, 20 ; in mammals, 
21 ; in articulates, 22 ; in crusta- 
ceans, 22 ; in radiates, 23. 

Nervous tissue, 15. 

Nest of Baltimore oriole, 46 ; of tai- 
lor bird, 46 ; of Ploceus, 47. 

Nomenclature, the naming of ob- 
jects and their classes, family, 

Notosaurus, 196. 

Nucleolites, 200. 

Nucleolus, a little nucleus, 14. 

Nucleus, a kernel, or condensed 
central portion, 14. 

Nudibranchiates, mollusks having 
the gills floating externally, fig. 91. 

Nummulites, 202. 

Nurses, of Cercaria, 130 ; ants and 
bees, 132. 

Nutrition, 72. 

Ocelli, minute eyes, 28. 
(Esophagus, the gullet, 22, 75. 
Olfactory, pertaining to the sense of 

smell, '21, 36. 
Omnivora, feeding upon all kinds of 

food, 83. 

Oolitic formation, 186. 
Operculum, a cover for the aperture 

of a shell. 
Opliidians, animals of the serpent 

kind, xvi. 
Optic nerves, 24. 
Orbits, 24. 
Orders, xiv. 
Organism, 7, 13. 
Organized bodies, general properties 

of, 11 ; elementary structure, 12. 
Ornithichuites, 197. 
Orthoceras fusiforme, 193. 
Osseous tissue, 15. 
Otolites, little bones in the ears of 

mollusks and Crustacea, 35. 
Ovary, the organ in which eggs 

originate, 104. 
Oviduct, the passage through which 

the egg is excluded, 105. 
Oviparous, producing eggs, 103. 
Ovis montana, 160. 
Ovo-viviparous, animals which hatch 

their eggs within their body, 105. 
Ovulation, the production of eggs, 


Oxygen, its consumption in respira- 
tion, 17, 95. 

Pachydermata, thick-skinned ani- 
mals, like the elephant, hog, &c. 
82 202. 

Paleontology, 183. 

Paleozoic age, 190, 191. 

Paleotherium, 202. 



Palpation, the exercise of the touch, 

Palpi, jointed organs for touch, about 
the mouth of insects, 40. 

Pancreas, 101. 

Papilla, a little pimple, 38. 

Paramecia, reproduction of, 126. 

Parasitic, living on other objects. 

Passerine, birds of the sparrow kind, 

Peduncle or Pedicle, a slender stem. 

Pelvis, the cavity formed by the hip- 
bones, 60. 

Pentacrinus, 199 ; metamorphosis 
of, 148. 

Perception, 43. 

Perchers, a class of birds, xvi. 

Peristaltic motion, 76. 

Petrifactions, 183. 

Pigment, a coloring substance, 27. 

Pituitary membrane, 37. 

Placenta, the organ by which the 
embryo of mammals is attached to 
the mother, 121. 

Placoids, fishes with a rough skin, 
like the shark or skate, xvi. 

Planaria, its digestive apparatus, 74 ; 
an eye of, 29. 

Plant-lice. See Aphides. 

Plants compared with animals, 16. 

Platynotus, 193. 

Pleiocene formation, 187. 

Plesiosaurus, 197, 200. 

Pleurotomaria, 201. 

Ploceus Philippinus, nest of, 47. 

Plutonic rocks, 182. 

Podurella, mode of leaping, 68; em- 
bryo of, 1 14 ; egg of, 104 ; repro- 
duction of, 125. 

Polyps, a small animal fixed at one 
end, with numerous flexible feel- 
ers at the other, 3, 29. 

Prehension, act of grasping, 85. 

Primary age, 195. 

Primitive stripe, 113. 

Progression, 66. 

Proligerous, the part of the egg 
where the embryo is placed, 111. 

Proteus, 177. 

Protosaurus, 196. 

Protractile, capable of being ex- 

Pterichthys, 194. 

Pterocoma pinnata, 199. 

Pterodactylus, 198. 

Pteropods, mollusks with wing-like 
expansions for swimming, xviii. 

Pulmonary, relating to the lungs, 90. 

Pulmonates, mollusks which breathe 

air, xviii. 
Pupil, 25. 
Pyrula, egg-cases of, 106. 

Quadrumanous, four-handed, 168. 
Quadruped, animals with four legs, 

Radiata, animals whose organs ra- 
diate from a centre, 3. 

Radius, one of the bones of the arm, 

Relation, functions of, 21. 

Reproduction, peculiar modes, 125. 

Reptiles, number of, 3 ; reign of, 
190, 195. 

Respiration, 92. 

Retractile, that may be drawn back, 

Rhizodonts, xvi ; of the trias, 196. 

Rhizopods, xix. 

Rocks, classification of, 183. 

Rodents, quadrupeds with teeth for 
gnawing, 83. 

Rotifers, jaws of, 79. 

Ruminants, quadrupeds which chew 
the cud. 

Running 1 , 67. 

Rytina Stelleri, 178. 

Salenia, 201. 

Saliferous formation, 186. 

Saliva, 83. 

Salivary glands, 100. 

Salpa, reproduction of, 128. 

Scansores, birds adapted for climb- 

inj?, xvi. 
Scaphites, 200. 
Scapula, 59. 
Sclerotic, the principal coat of the 

eye, 25. 

Scutella, jaws of, 77. 
Sea-anemone. See Actinia. 
Sea-urcliin, eye of, 29 ; digestive 

organs, 74. 

Secondary age, 190, 195. 
Secretions, 98. 
Sedimentary rocks, 183. 
Segment, portion of a circle or 


Sensation, general, 19, 23. 
Senses, special, 23. 
Serous, watery, 112. 
Shark, egg of,' 104. 
Shoulder-blade, 58. 
Sight, 24. 
Silex, ilinty rock. 



Siliceous, made of flint. 

Silk- worm, metamorphosis of, 143. 

Silurian rocks, lower, 185 ; upper, 

Sinuous, bending in and out, xvii. 

Siphonophori, xviii. 

Siren, 177. 

Skeleton, 51, 53. 

Skin, structure of, 99. 

Smell, 36. 

Species, the common name of a 
thing ; constancy of, 43 ; defini- 
tion of, 

Spinal marrow, 21. 

Spondyli, 201. 

Sponges not animal, 17. 

Spontaneous generation, 140. 

Standing, 64. 

Stapes, 33. 

Star-fish, metamorphoses of, 146 ; 
eye of, 26 ; mode of progression, 
57; reproduction of parts, 126. 

Stigmata, openings in insects for the 
admission of air, 92. 

Stomach, 73. 

Stratified rocks, 183. 

Stratum, a layer. 

Strobila, 133, 138. 

Structure of the earth's crust, 182. 

Sturgeon, compared with white-fish, 

Suctoria, insects talcing their food by 
suction, xvii. 

Swimming, 69. 

Sylvia sutoria, nest of, 46. 

Systole, the contraction of the heart 
to force out the blood, 90. 

Tape-worm, reproduction of, 140. 

Tarsus, the ancle. 

Taste, 38. 

Teeth, 79. 

Temperate faunas, 166. 

Temporal, relating to the temples, 

Tentacle, the horn-like organs on the 
head of mollusks, usually bearing 
the eyes, 28. 

Terebratula, 198. 

Tertiary age, 190, 201. 

Tertiary formation, lower, 186 ; up- 
per, 187. 

Test, the bristle crust covering the 
crustaceans, &c. 51. 

Teuthideans, the family of cuttle- 
fishes, xvii. 

Tibia, one of the bones of the leg, 63. 

Tissues, 13 ; areolar, 14 ; cartilagi- 
nous, 14 ; osseous, 15 ; nervous, 

Tongue, 38. 

Touch, 39. 

Trachea, the windpipe, 93. 

Tracheae, the air-tubes of insects, 92. 

Trias formation, 186, 196. 

Trisfunia, 198. 

Trilobites, 9, 193, xvii. 

Trocholites ammdnius, 193. 

Trophi, organs for feeding, of insects, 
crabs, &c. 

Tropical faunas, 172. 

Trot, 67. 

Tubulibranchiates, xvii. 

Tunicata, mollusks with a leathery 
covering 1 , 128. 

Turrilites, 200. 

Tympanum, a drum ; the membrane 
separating the internal and exter- 
nal ear, 33. 

Type, an ideal image. See p. 

Ulna one of the bones of the arm, 


Ultimate, final. 
Univalve, having a single shell, like 

the snail, 3. 

Vascular, composed of vessels, 99. 

Vegetative life, 20 ; layer, 112. 

Veins, 88. 

Ventricle, a cavity of the heart, 89. 

Vermicular, 76. 

Vertebra, a joint of the back-bone, 

Vertebrate, having a back-bone, 3. 

Vertical, in a perpendicular direc- 
tion, 24. 

Vesicle, a small membranous bag. 

Vestibule, a porch ; the entrance to 
one of the cavities of the ear, 34. 

Vibratile, moving to and fro, 87. 

Viscera, 128. 

Vitelline membrane, 108. 

Vitellus, 108. 

Vitreous humor, 26. 

Viviparous, producing living youns, 

Vocal cords, 41. 

Voice, 40. 

Voluntary, under control of the will, 

Vorticella, reproduction of, 126. 



Walking, 66. 

Warm-blooded animals, 96. 

Water-tubes of aquatic animals, 97. 

Whale, fans of, 80. 

Whales, mode of swimming, 70. 

White-fish, development of, 115. 

Worms, eye of, 29. 

Zoology, its sphere, 1. 

Zoophytes, animals of a very low 

type, mostly fixed to the ground 

of a plant-like form. 






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to be remunerated only by a very extensive sale." 

" The selections given by Mr. Chambers from the works of the early English writers are 
copious, and judiciously made. ***** We shall conclude as we commenced, with ex- 
pressing a hope that the publication which has called forth our remarks will exert an influ- 
ence in directing the attention of the public to the literature of our forefathers." 

North American Review. 

CHAMBERS'S MISCELLANY of Useful and Entertaining Knowledge, 
with elegant illustrative engravings. Edited by WILLIAM CHAMBERS. 
Price 25 cents per number, to be completed in ten Elegant volumes. 

*** The design of the MISCELLANY is to supply the increasing demand for useful, in- 
structive, and entertaining reading, and to bring all the aids of literature to bear on the cul- 
tivation of the fcelimjs and imdcrstdndiity of the people to impress correct views on impor- 
tant moral and social questions suppress every species of strife and savagery cheer the 
lagging and desponding by the relation of tales drawn from the imagination of popular 
writers rouse the fancy by descriptions of interesting foreign scenes give a zest to 
every-day occupations by ballad and lyrical poetry in short, to furnish an unobtrusive 
friend and guide, a lively fireside companion, as far as that object can be attained through 
the instrumentality of books. 

books, elegantly illuminated. Edited by WILLIAM CHAMBERS. Each 
volume forms a" complete work, embellished with a fine steel engraving, 
and is sold separately. Price 37 J cents. 

THE LITTLE ROBINSON: And other Tales. 
TRUTH AND TRUST. Jervis Ryland Victor and Lisette. 
JACOPO : Tales by Miss EDGEWORTH and others. 
POEMS. By various Authors, for the young. 

The aim of this series is to make the young reader better and happier ; to this end, th' 
selection of subjects will be designed to influence the heart and feelings. 

0^= Other volumes are in preparation. 

Valuable Sdjoot Books. 

the Use of Common Schools. By J. L. BLAKK, D.D. Illustrated by 
Steel Plate Engravings. 8vo. cloth back. Price 50 cents. 

From E. Hinckley, Professor of Mathematics in Maryland University. 

" I am much indebted to you for a copy of the First Book in Astronomy. It is a work 
of utility and merit, tar superior to auy other which I have seen. The author has selected 
his topics with great judgment, arranged them in admirable order, exhibited them in 
a style and manner at once tasteful and philosophical. Nothing seems wanting, nothing 
redundant. It is truly a very beautiful and attractive book, calculated to aflbrd both 
pleasure and profit to all who "may enjoy the advantage of perusing it." 

From B. Field, Principal of the Hancock School, Boston. 

" I know of no other work on Astronomy so well calculated to interest and instruct 
young learners in this sublime science." 

From James F. Gould, A.M., Principal of the High School for Young Ladies, 

Baltimore, JtlJ. 

"I shall introduce your First Book in Astronomy into my Academy in September, 
consider it decidedly superior to any elementary work of the kind I have ever seen." 

From Isaac Foster, Instructor of Youth, Portland. 

"I have examined Blake's First Book in Astronomy, and am much pleased with it. A 
very happy selection of topics is presented in a manner which cannot fail to interest the 
learner, while the questions will assist him materially in fixing in the memory what ought 
to be retained. It leaves the most intricate parts of the subject for those who are able to 
master them, and brings before the young pupil only what can be made intelligible and 
interesting to him." 

" The illustrations, both pictorial and verbal, are admirably intelligible ; and the defini- 
tions are such as to be easily comprehended by juvenile scholars. The author has inter- 
woven with his scientific instructions much interesting historical information, and con- 
trived to dress his philosophy in a garb truly attractive. -V. i*. Daily Ei cnunj Journal. 

" We are free to say. that it is, in our opinion, decidedly the best work we have any 
knowledge of, on the sublime and interesting subject of Astronomy. The engravings are 
executed in a superior style, and the mechanical appearance of the book is extremely 
prepossessing. The knowledge imparted is in language at once chaste, elegant, and 
simple adapted to the comprehension of those for whom it was designed. The subject 
matter is selected with great judgment, and evinces uncommon industry and research. 
\Ve earnestly hope that parents and teachers will examine and judge for themselves, as 
we feel confident they will coincide with us in opinion. We only hope the circulation of 
the work will be commensurate with its merits." Boston Evening Gazette. 

" The book now before us contains forty-two short lessons, with a few additional ones, 
which are appended in the form of problems, with a design to exercise the young learner 
in finding out the latitude and longitude on the terrestrial globe. We do not hesitate to 
recommend it to the notice of the superintending committees, teachers, and pupils of our 
public schools. The definitions in the first part of the volume are given in brief and clear 
language, adapted to the understanding of beginners." State Herald, Portsmouth, X. H. 

BLAKE'S NATURAL PHILOSOPHY. Being Conversations on 
Philosophy, with the addition of Explanatory Note?, Questions for Exami- 
nation, and a Dictionary of Philosophical Terms. With twenty-eight steel 
Engravings. By J. L. 'BLAKE, D.D. 12mo. sheep. Price 67 cents. 

*** Perhaps no work has contributed so much as this to excite a fondness for the study 
of Natural Philosophy in youthful minds. The familiar comparisons, with which it 
abounds, awaken interest, and rivet the attention of the pupil. 

From Rev. J. Adams, President of Charleston College, S. C. 

"I have 
Natural Philos 
additions to 
acquainted. I shall recommend it wherever I have an opportunity.' 

"We avail ourselves of the opportunity furnished us by the publication of a new edition 
of this deservedly popular work, to recommend it. not only to those instructors who may 
not already have" adopted it, but also generally to all readers who are desirous of obtaining 
informatio'n on the subjects on which it treats. By Questions arranged at the bottom of 
the pages, in which the collateral facts are arranged, he directs the attention of the learner 
to the principal topics. Mr. Blake has also added many Notes, which illustrate the pas- 
sages to which they are appended, and the Dictionaiy of Philosophical Terms is a useful 
addition," U. S. Literary Gazette. 

Valuable Sdjool 33ook0. 

Lessons for Reading hi Prose and Verse. By E. BAILEY. A.M., 
late Principal of the Noting Ladies' High School, Boston. Stereotyped 
Edition. 12mo. sheep. Price 83X cents. 

From the Principals of the Public Schools for Females, Boston. 

" GENTLEMEN : We have examined the Young Ladies' Class Book with interest and 
pleasure ; with interest, because we have felt the want of a Reading Book expressly de- 
signed for the use of females; and with pleasure, because we have found it well adapted 
to supply the dericiency. In the selections for a Reader designed for boys, the eloquence 
of the bar, the pulpit, and the forum may be laid under heavy contribution ; but such 
selections, we conceive, are out of place in a book designed for females. We have been 
pleased, therefore, to observe, that in the Young Ladies' Class Book such pieces are rare. 
The high-toned morality, the freedom from sectarianism, the taste, richness, and adapta- 
tion of the selections, added to the neatness of its external appearance, must commend it to 
all; while the practical teacher will not fail to observe that diversity of style, together with 
those peculiar points, the want of which, few, who have not felt, know how to supply. 



From the Principal of the Mount Vernon School, Boston. 

"I have examined with much interest the Young Ladies' Class Book, by Mr. Bailey 
and have been very highly pleased with its contents. It is my intention to introduce it 
into my own school ; as I regard it as not only remarkably well fitted to answer its particu- 
lar object as a book of exercises in the art of elocution, but as calculated to have an influ- 
ence upon the character and conduct, which will be in every respect favorable. 


"We were never so struck with the importance of having reading books for female 
schools, adapted particularly to that express purpose, as while looking over the pages of 
this selection. The eminent success of the compiler in teaching this branch, to which we 
can personally bear testimony, is sufficient evidence of the character of the work, consid- 
ered as a selection of lessons in elocution ; they are, in general, admirably adapted to 
cultivate the amiable and gentle traits of the female character, as well as to elevate and 
improve the mind." Ann'ils of Education. 

" The reading books prepared for academic use, are often unsuitable for females. We 
are glad, therefore, to perceive that an attempt has been made to supply the deficiency ; and 
we believe that the task has been faithfully and successfully accomplished. The selections 
are judicious and chaste ; and so far as they have any moral bearing, appear to be unex- 
ceptionable." Education Reporter. 


By C. K. DILLAWAY, A.M., late Principal in the Boston Latin School. 
With Engravings. Eighth EcL, improved. 12mo. half mor. Price 67 cts. 

From E. Bailey, Principal of the Young Ladies' High School, Boston. 

" Having used Dillaicay's Roman Antiquities and Ancient Mythology in my school for 
several years, I commend it to teachers with great confidence, as a valuable text-book on, 
those interesting branches of education. E. BAILEY.' 

" The want of a cheap volume, embracing a succinct account of ancient customs, 
together with a view of classical mythology, has long been felt. To the student of a lan- 
guage, some knowledge of the manners, habits, and religious feelings of the people whose 
language is studied is indispensably requisite. This knowledge is seldom to be obtained 
without tedious research or laborious investigation. Mr. Dillaway's book seems to have 
been prepared with special reference to the wants of those who are just entering upon a 
classical career; and we deem it but a simple act of justice to say, that it supplies the 
want, which, as we have before said, has long been felt. In a small duodecimo, of about 
one hundred and fifty pages, he concentrates the most valuable and interesting particulars 
relating to Roman antiquity ; together with as full an account of heathen mythology as is 
generally needed in our highest seminaries. A peculiar merit of this compilation, and 
one which will gain it admission into our highly respectable female seminaries, is the total 
absence of all allusion, even the most remote, to the disgusting obscenities of ancient 
mythology; while, at the same time, nothing is omitted which a pure mind would feel 
interested to know. We recommend the book as a valuable addition to the treatises in 
our schools and academies." Education Reporter, Boston. 

"We well remember, in the days of our pupilage, how unpopular as a study was tho 
volume of Roman Antiquities introduced in the academic course. It wearied on account 
of its prolixity, filling a thick octavo, and was the prescribed task each afternoon for a 
long three months. It was reserved for one of our Boston instructors to apply the con- 
densing apparatus to this mass of crudities, and so to modernize the antiquities of the old 
Romans, as to make a befitting abridgment for schools of the first order. Mr. Dillaway has 
presented such a compilation as must be interesting to lads, and become popular as a text- 
book. Historical facts are stated with great simplicity and clearness ; the most important 
points ore seised upon, while trifling peculiarities are passed unnoticed." Am. Traveller. 


THE CHRISTIAN'S DAI LY TREASURY. A Religious Exercise for 
every day in the Year. By Rev. EKENEZER TEMPLE. Price $1.00 

=%:* This work is strictly evangelical, and presents with great distinctness the peculiar 
points of orthodoxy. The texts are happily chosen, and all the thoughts suggested by 
the author are interesting and profitable. The skeletons are generally of the textual 
character, very neat, comprehensive, and each of them contains matter enough for a 
sermon. There is a great variety of beautiful gems scattered through it, both original 
and selected, 

This work might appropriately be called a guide to meditation. It consists of a subject 
for ever}' day in the year, drawn from an appropriate portion of Scripture, with reflections 
upon it." It does not attempt to exhaust the daily subjects, but merely to direct the read- 
er's thoughts. The plan strikes us as a very happy one. Many do not know how to medi- 
tate. A careful use of this volume, for a year, will do very much to form habits of profita- 
ble meditation on Scripture. As habits" of meditation are so intimately connected with 
Christian progress and enjoyment, we think the influence of such a work as is here pre- 
sented, must be very happy. Ohristicm Chronicle, Philadelphia. 

One of the best books of the kind we have recently met with. The daily reflections, 
instead of being general and diffuse, are thrown into the sermonic form, and thus the 
instruction is made more impressive and easy of retention. 

York Commercial Advertiser. 

LEARNING TO ACT. An interesting and instructive work for the 
Young. With numerous illustrations. Price 37>a cents. 

LEARNING TO FEEL. An interesting and instructive work for the 
Young. With numerous illustrations. Price 37>z cents. 

LEARNING TO THINK. An interesting and instructive work for the 
Young. With numerous Illustrations. Price 37I- cents. 


Abridged by B. FAWCETT, A.M. Fine Edition. ' Price 50 cents. 

" I am gratified to perceive that you have published a handsome edition of Baxter's 
Saint's Best. Of the value of the work itself, it is superfluous to speak. It has few equals 
in any language. The ordinary copies are palpably beneath the value of the work." 
Rev. Dr. Wayland, President oj Brown University. 

CUMMINGS. Price 62^ Cents. 

MEMOIR OF HARLAN PAGE; Or the Power of Prayer and 
Personal Effort for the Souls of Individuals. By War. A. HALLOCK. 
Price 3732 cents. 

JOHN ANGELL JAMES. Price 37>a cents. 


Price 37 3a cents. 

A N EC DOT ES for the Family and Social Circle. Upwards of 300 instruc- 
tive Anecdotes, illustrating important truths. Price 62>a cents. 

BUCK'S RELIGIOUS EXPERIENCE; A Treatise in which its 
Nature, Evidence, and Advantages are considered. By Rev. CHAP.LES 
BUCK, D.D. Price 50 cents. 

as to their Moral tendency. By ANDREW FULLER. Price 50 cents. 

VITAL CHRISTIANITY: Essays and Discourses on the Religions of 
Man and the Religion of God. By A. Vinet, D.D. Translated, with an 
Introduction. Bv Rev. ROBERT TURNBULL. Price $1.13. 



its government and simple in its worship. By LYMAN COLEMAN. With 
an introductory essay, by Dr. AUGUSTUS NEANDER, of Berlin. Second 
Edition. Price $1.25. 

The Publishers have been favored with many highly commendatory notices of this 
work, from individuals and public journals. The first edition found a rapid sale; it has 
been republished in England, and received with much favor; it is universally pronounced 
to be standard authority on this subject ; and is adopted as a Text Book in Theological 

From the Professors in Andover Theological Seminary. 

" The undersigned are pleased to hear that you are soon to publish a new edition of the 
'Primitive Church,' by LYMAN COLEMAN. They regard this volume as the result of 
extensive and original research ; as embodying very important materials for reference, 
much sound thought and conclusive argument. In their estimation, it may both interest 
and instruct the intelligent layman, may be profitably used as a Text Book for Theologi- 
cal Students, and should especially form a part of the libraries of clergymen. The intro- 
duction, by NEANDER, is of itself sufficient to recommend the volume to the literary 


From Samuel Miller, D.D., Princeton Theological Seminary. 

" Gentlemen, I am truly gratified to find that the Rev. Mr. COLEMAN'S work on the 
'Apostolical and Primitive Church,' is so soon to reach a second edition. It is, in my 
judgment, executed with learning, skill, and fidelity; and it will give me great pleasure to 
learii that it is in the hands of every minister, and every candidate for the" ministry in our 
land, and indeed of every one who is disposed, and who wishes for enlightened and safe 
guidance, on the great subject of which it treats." 

Yours, respectfully, SAMUEL MILLER. 

THE CHURCH MEMBER'S MANUAL Of Ecclesiastical Principles, 
Doctrines, and Discipline ; presenting a Systematic View of the Structure, 
Polity, Doctrines, and Practices of Christian Churches, as taught in the 
Scriptures ; by WM. CROWELL. With an Introductory Essay, by HENRY 
J. KIPLEY, D.D. Price 90 cents. 

The Rer. J. Dowling, D.D., of New York, writes : " I have perused, with great satis- 
faction ' The Church Member's Manual.' I have long felt in common with many of my 
ministering brethren, the need of just such a work to put into the hands of the members, 
and especially the pastors and deacons of our churches. . . As a whole, I have great 
pleasure in commending the work to the attention of all Baptists. I think that Bro. Crowell 
has performed his task in an admirable manner, and deserves the thanks of the whole Bap- 
tist community." 

We cordially concur in the above recommendation. S. H. Cone, Elisha Tucker, W. W. 
Evarts, David Bellamy, Henry Davis, A. N. Mason, and A. Haynes. 

The pastor of one of the largest and most influential churches in New England, writes 
as follows . 

" The work is admirably adapted to the wants of pastors and private members. If I 
could have my wish, not only the ministers, but the deacons and senior members of our 
churches would own and read the book." 

Another writes " I have read this work with great pleasure. For a long time such a 
guide has been needed, and much detriment to the church would have been avoided, hud 
it made its appearance sooner." 

" This very complete Manual of Church Polity is all that could be desired in this depart- 
ment. Every important point within a wide range, is brought forward, and every point 
touched is settled." Christian Review. 

" While we dissent from the positions laid down in this book, yet we honor the author for 
carrying out his principles. He undertook to write a Baptist book, and we cheerfully 
bear testimony that he has done his work and done it well. We bear testimony to the 
depth of thought and conciseness and purity of style which do credit to the author." 

Christian Witness (Episcopal). 

by Rev. J. 0. CHOULES. New Edition ; with an Introductory Essay, by 
Rev. HUBBARD WINSLOW. Price 38 cents. 

A pastor writes "I sincerely wish that every professor of religion in the land may 
possess this excellent manual. I am anxious that every member of my church should 
possess it, and shall be linppy to promote its circulation still more extensively." 

"The spontaneous effusion of our heart, on laying the book down, was, may every 
church-member in our land soon possess this book, and be blessed with all the happiness 
which conformity to its evangelic sentiments and directions is calculated to confer." 

Christian Secretary. 


CLASSICAL STUDIES: Essays on Ancient Literature and Art. 
With the Biography and Correspondence of eminent Philologists. By 
BARNAS SEARS, Pres. Newton Theol. Inst., B. B. EDWARDS, Prof. 
Andover Theol. Seminary, and C. C. FELTON, Prof. Harvard University. 
Price $1.25. 

"This volume is no common-place production. It is truly refreshing, when we are 
obliged, from week to week, to look through the mass of books which increases upon our 
table, many of which are extremely attenuated in thought and jejune in style, to find some- 
thing which carries us back to the pure and invigorating influence of the master minds of 
antiquity. The gentlemen who have produced this volume deserve the cordial thanks of 
the literary world." New England Puritan. 

" The object of the accomplished gentlemen who have engaged in its preparation has 
been, to foster and exteud among educated men, in this country, the already growing inter- 
est in classical studies. The design is a noble and generous one, and has been executed 
with a taste and good sense that do honor both to the writers and the publishers. The book 
is one which deserves a place in the library of every educated man. To those now engaged 
in classical study it cannot fail to be highly useful, while to the more advanced scholar, it 
will open new sources of interest and delight in the unforgotteii pursuits of his earlier 
days." Providence Journal. 

GESENIUS'S HEBREW GRAMMAR. Translated from the Eleventh 
German Edition. By T. J. CONANT, Prof, of Hebrew and of Biblical 
Criticism and Interpretation in the Theol. Institution at Hamilton, N. Y. 
With a Course of Exercises in Hebrew Grammar, and a Hebrew Chres- 
tomathy, prepared by the Translator. Price $2.00. 

" *** Special reference has been had in the arrangement, illustrations, the addition of the 
Course of Exercises, the Chrestomathy, &c., to adapt it to the wants of those who may wish 
to pursue the study of Hebrew without the aid of a teacher. 

Prof. Stewart, in an article in the Biblical Repository, says : " With such efforts, such 
uuremitted, unwearied, energetic efforts, what are we to expect from such a man as 
Gesenius? Has he talent, judgment, tact, as a philologist? Read his work on Isaiah ; 
compare his Hebrew Grammar with the other grammars of the Hebrew which Germany has 
yet produced ; read and compare any twenty, or even ten articles on any of the difficult and 
important words in the Hebrew with the same in Buxtorff, Cocceius, Stockins, Eichhorn's 
Sinioui, Winer, even (Parkhurst, I cannot once name), and then say whether Gesenius, as 
a Hebrew philologer, has talents, tact, and judgment. Nothing but rival feelings, or preju- 
dice, or antipathy to his theological sentiments, can prevent a unity of answer." 

of the German Work of Dr. G. E. Guhrauer. By JOHN M. MACK.IE. 
Price 75 cents. 

" The peculiar relation which Liebnitz sustained during his life to Locke and Newton 
may partly account for the fact that a biography of this great man has been so long wanting 
in the English language. . . . We commend this book, not only to scholars and men 
of science, but to all our readers who love to contemplate the life and labors of a great and 
good man. It merits the special notice of all who are interested in the business of education, 
and deserves a place by the side of Brewster's Life of Newton, in all the libraries of our 
schools, academies, and literary institutions." Christian Watchman. 

" There is perhaps no case on record of a single man who has so gone the rounds of human 
knowledge as did Liebuitz : he was not a recluse, like Spinoza and Kant, but went from 
capital to capital, and associated with kings and premiers. All branches of thought were 
interesting to him, and he seems in pursuing all to have been actuated not by ambition, 
but by a sincere a desire to promote the knowledge and welfare of mankind. Ohrist. World. 

LIFE OF ROGER Wl L LI A MS, The Founder of the State of Rhode 
Island. By WM. GAMMELL, Professor of Rhetoric in Brown University. 
With a likeness. Price 75 cents. 

" Mr. GarumelPs fine belles-letters attainments have enabled him to present his distin- 
guished subject in the most captivating light. So far as the work touches controversies 
which reach and influence the present times, it is our privilege as well as duty to read it as a 
private citizen, and not as a public journalist. Its mechanical execution is in the usually neat 
style of the respectable publishers." Christian Alliance. 

" This life has many virtues brevity, simplicity, fairness. Though written by a Rhode 
Island man, and warm in its approval of Roger Williams, it is not unjust to his Puritan 
opponents, but only draws such deductions as were unavoidable from the premises. It is 
the life of a good man, and we read with grateful complacency the commendation of his 
excellences." Christian World. 



THE MISSIONARY ENTERPRISE; A Collection of Discourses 

on Christian Missions, by American Authors. Edited by BAKON 
STOW, D.D. Second Thousand. Price 85 cents. 

" If we desired to put into the hands of a foreigner a fair exhibition of the capacity and 
spirit of the American church, we would give him this volume. You have here thrown 
together a few discourses, preached from time to time, by different individuals, of different 
denominations, as circumstances have demanded them ; and you see the stature and feel 
the pulse of the American Church in these discourses with a certainty not to be mistaken. 

" You see the high talent of the American church. "We venture the assertion, that no 
nation in the world has such an amount of forceful, available talent in its pulpit. The 
energy, directness, scope, and intellectual spirit of the American church is wonderful. In 
this book, the discourses by Dr. Beecher, Pres. Wayland, and the Rev. Dr. Stone of the 
Episcopal church, are among the very highest exhibitions of logical correctness, and burn- 
ing, popular fervor. This volume will have a wide circulation." The New Evglander. 

" This work contains fifteen sermons on Missions, by Rev. Drs. Wayland, Griffin, Ander- 
son, Williams, Beecher, Miller, Fuller. Bernan, Stone, Mason, and by Rev. Messrs. Kirk, 
Stow, and Ide. It is a rich treasure, which ought to be in the possession of every American 
Christian." Carolina Baptist. 

THE GREAT COMMISSION; Or, the Christian Church constituted 
and charged to convey the Gospel to the World. A Prize Essay. By 
JOHN HARRIS, D.D. With an Introductory Essay, by W. R. WILLIAMS, 
D.D. Fifth Thousand. Price $1.00. 

" His plan is original and comprehensive. In filling it up the author has interwoven 
facts with rich and glowing illustrations, and with trains of thought that are sometimes 
almost resistless in their appeals to the conscience. The work is not more distinguished 
for its arguments and its genius, than for the spirit of deep and fervent piety that per- 
vades \t." T/te Dayspring. 

" This work comes forth in circumstances which give and promise extraordinary interest 
and value. Its general circulation will do much good." New York Evangelist. 

"In this volume we have a work of great excellence, rich in thought and illustration of a 
subject to which the attention of thousands has been called by the word and providence of 
God." Philadelphia Observer. 

" The merits of the book entitle it to more than a prize of money. It constitutes a most 
powerful appeal on the subject of Missions." New York Baptist Advocate. 

" Its style is remarkably chaste and elegant. Its sentiments richly and fervently evan- 
gelized, its argumentation conclusive. Preachers especially should read it; they will re- 
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" To recommend this work to the friends of missions of all denominations would be but 
faint praise; the author deserves and will undoubtedly receive the credit of having applied 
a new lever to that great moral machine which, by the blessing of God, is destined to 
evangelize the world." Christian Secretary, Hartford. 

"We hope that the volume will be attentively and prayerfully read by the whole 
church, which are clothed with the " Great Commission " to evangelize the world, and 
that they will be moved to an immediate discharge of its high and momentous obligations. 

.ZV. E. Puritan, Boston. 

THE KAREN APOSTLE; Or, Memoir of Ko THAH-BYU, the first 
Karen convert, with notices concerning his Nation. W T ith maps and 
plates. By the Rev. FRANCIS MASON, ^Missionary. American Edition. 
Edited by Prof. H. J. RIPLEY, of Newton Theol. Institution. Fifth Thou- 
sand. Price 25 cents. 

*#* " This is a work of thrilling interest, containing the history of a remarkable man, and 
giving, also, much information respecting the Karen Mission, heretofore unknown in this 
country. It must be sought for, and read with avidity by those interested in this most in- 
teresting mission. It gives an account, which must be attractive, from its novelty, of a 
people that have been but little known and visited by missionaries, till within a few years* 
The baptism of Ko Thah-Byu, in 1828, was the beginning of the mission, and at the end of 
these twelve years, twelve hundred and seventy Karens are officially reported as members 
of the churches, in good standing. The mission has been carried on pre-eminently by the 
Karens themselves, and there is no doubt, from much touching evidence contained in this 
volume, that they are a people peculiarly susceptible to religious impressions. The account 
of Mr. Mason must be interesting to every one. 



MEMOIR OF ANN H. JUDSON, late Missionary to Burmali. By Rev. 
JAMES D. KNOWLES. 12mo. Edition, price 85 cents. ISmo., price 58 cts. 

" We are particularly gratified to perceive a new edition of the Memoirs of Mrs. Judson. 
She was an honor to our country one of the most noble-spirited of her sex. It cannot, 
therefore, be surprising, that so many editions, and so many thousand copies of her life and 
adventures have been sold. The name the long career of suffering the self-sacriticing 
spirit of the retired country-girl, have spread over the whole world ; and the heroism of her 
apostleship and almost martyrdom, stands out a living and heavenly beacon-tire, amid the 
dark midnight of ages, and human history and exploits. She was the first woman who 
resolved to become a missionary to heathen countries." American Traveller. 

" This is one of the most interesting pieces of female biography which has ever come un- 
der our notice. No quotation, which our limits allow, would do justice to the facts, and we 
must, therefore, refer our readers to the volume itself. It ought to be immediately added to 
every family library." London Miscellany. 

Burmah, containing much intelligence relative to the Burman Mission. 
By Rev. ALONZO KING. A new Edition. With an Introductory Essay, 
by a distinguished Clergyman. Embellished with a Likeness ; a 
beautiful Vignette, representing the baptismal scene just before his 
death ; and a drawing of his tomb, taken by Rev. H. MALCOM, D.D. 
Price 75 cents. 

" One of the brightest luminaries of Burmah is extinguished, dear brother Boardman 
is gone to his eternal rest. He fell gloriously at the head of his troops in the arms of vic- 
tory, thirty-eight wild Karens having been brought into the camp of king Jesus since the 
beginning of the year, besides the thirty-two that were brought in during the two preceding 
years. Disabled by wounds, he was obliged, through the whole of the last expedition, to be 
carried on a litter ; but his presence was a host, and the Holy Spirit accompanied his 
dying whispers with almighty influence." REV. DR. JUDSOX. 

' : No one can read the Memoir of Boardman, -without feeling that the religion of Christ is 
suited to purify the affections, exalt the purposes, and give energy to the character. Mr. 
Boardman was a man of rare excellence, and his biographer, by a just exhibition of that 
excellence, has rendered an important service, not only to the cause of Christian missions) 
but to the interests of personal godliness." BAKON STOW. 

Female Missionary to China. By Rev. J. B. JETER. Fourth thousand. 
Price 50 cents. 

" We have seldom taken into our hands a more beautiful book than this, and we have 
no small pleasure in knowing the degree of perfection attained in this country in the arts 
of printing and book-binding, as seen in its appearance. The style of the author is sedate 
and perspicuous, such as we might expect from his known piety and learning, his attach- 
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GOULD, KENDALL & LINCOLN are happy to announce that they have 
completed arrangements with the Messrs. Chambers, of Edinburgh, for the 
re-publication, in semi-monthly numbers, of CHAMBERS'S MISCELLANY. 
The first number will be issued in July, and continued at regular intervals 
until the work is completed. 

The design of the MISCELLANY is to supply the increasing demand for 
useful, instructive, and entertaining reading, and to bring all the aids of 
literature to bear on the cultivation of the feelings and understandings of 
the people to impress correct views on important moral and social ques- 
tions suppress every species of strife and savagery cheer the lagging 
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etry in short, to furnish an unobtrusive friend and guide, a lively fireside 
companion, as far as that object can be attained through the instrumentality 
of books. 

The universally acknowledged merits of the CYCLOPAEDIA OF ENGLISH 
LITERATURE, by the Chambers', connected with its rapid sale, and the 
unbounded commendation bestowed by the press, give the publishers full 
confidence in the real value and entire success of the present work. 

The subjoined table of contents of the first two volumes will give the best 
idea of the comprehensive character and diversified contents of this work : 

VOL. I. 

No. 1. Life of Louis Philippe. 
Tale of Norfolk Island. 
Story of Colbert. 
The Employer and Employed. 
Time Enough. By Mrs. S. 0. Hall. 
Manual for Infant Management. 
Piccioli, or the Prison Flower. 
Life in the Bash. By a Lady. 

No. 2. William Tell and Switzerland. 

The Two Beggar Boys. A Tale. 
Poems of the Domestic Affections. 
Life of Grace Darling, &c. 
Story of Maurice and Genevieve. 
Religious Imposters. 
Anecdotes of Dogs. 

No. 3. La Rochejaquelein and the War in 

La Vendee. 

Journal of a Poor Yicar. 
Romance of Geology. 
History of the Slave Trade. 
Walter Ruysdael. the Watchmaker. 
Chevy-Chase, and the Beggar's 
Daughter of Bethnal-Green. 

VOL. n. 

No. 4. Life of Nelson. 

The Temperance Movement. 
Story of Peter Williamson. 
Joan of Arc, Maid of Orleans. 
Annals of the Poor Female In- 
dustry and Intrepidity. 
Slavery in America. 

No. 5. A Visit to Vesuvius, Pompeii, and 

Story of Baptiste Lulli. 

Select Poems of Kindness to Ani- 

Wallace and Bruce. 

Cases of Circumstantial Evidence. 

Story of Richard Falconer, &c. 

No. 6. The Goldmaker's Village. 

The Last Earl of Derwentwater. 
The Heroine of Siberia. 
Domestic Flower-Culture. 
Insurrections in Lyons. 
The Hermit of Warkworth, and 
Other Ballads. 

Each number will form a complete work, and every third number will be furnished 
with a title page and table of contents, thus forming a beautifully illustrated VOLUME 
of over 500 pages, of useful and entertaining reading, adapted to every class of readers. 
The whole to be completed in THIRTY NUMBERS, forming TEN ELEGANT VOLUMES. 

d?" This work can be sent by mail to any part of the country. A direct remittance 
to the publishers of six DOLLARS will pay for the entire work. This liberal discount 
for advance pay will nearly cover the cost of postage on the work. Those wishing for 
one or more sample numbers can remit accordingly. 

Qp=" Booksellers and Agents supplied on the most liberal terms. 







Complete in two imperial octavo volumes, of more than fourteen hundred pages of 

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American public, originated in a desire to supply the great body of the peo- 
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work without being struck with its beauty and cheapness. The editor, 
Robert Chambers, is distinguished as the author of many valuable works, 
and as joint editor of Chambers's Edinburgh Journal. 

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As an evidence of the great popularity of the work in England, it may be 
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In addition to the great number of pictorial illustrations given in the 
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[p~ Booksellers and Agents supplied on the most liberal terms.